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In this study, the degradation characteristics of radio frequency (RF)-low-noise amplifiers (LNA) due to a total ionizing dose (TID) is investigated. As a device-under-test (DUT), sample LNAs were prepared using silicon–germanium (SiGe) heterojunction bipolar transistors (HBTs) as core elements. The LNA was based on a cascode stage with emitter degeneration for narrowband applications. By using a simplified small-signal model of a SiGe HBT, design equations such as gain, impedance matching, and noise figure (NF) were derived for analyzing TID-induced degradations in the circuit-level performance. To study radiation effects in circuits, the SiGe-RF-LNAs fabricated in a commercial 350 nm SiGe technology were exposed to 10-keV X-rays to a total ionizing dose of up to 3 Mrad(SiO2). The TID-induced performance changes of the LNA were modeled by applying degradation to device parameters. In the modeling process, new parameter values after irradiation were estimated based on information in the literature, without direct measurements of SiGe HBTs used in the LNA chip. As a result, the relative contributions of parameters on the circuit metrics were compared, identifying dominant parameters for degradation modeling. For the TID effects on input matching (S11) and NF, the base resistance (RB) and the base-to-emitter capacitance (Cπ) of the input transistor were mostly responsible, whereas the transconductances (gm) played a key role in the output matching (S22) and gain (S21). To validate the proposed approach, it has been applied to a different LNA in the literature and the modeling results predicted the TID-induced degradations within reasonable ranges. [ABSTRACT FROM AUTHOR]

RF PAs need to be reliable enough to protect them from damage under load mismatch conditions. This paper investigated the characteristics of GaAs heterojunction bipolar transistors (HBTs) under load mismatch conditions using a novel reverse wave injection technique to realize large VSWR ruggedness measurement with the circle centered at 50 Ohm and optimal impedance separately to analyze the device in real applications. With a real-time waveform measurement system, the RF voltage and current waveform information can be acquired, which provide a more-accurate view of what is occurring at the current generator plane of the HBT device. Thereby, the potential failure mechanisms and load impedance can be identified to design the most-suitable PA circuits in communication systems. [ABSTRACT FROM AUTHOR]

With the development and popularization of the Beidou-3 navigation satellite system (BDS-3), to ensure its unique short message function, it is necessary to integrate a radio frequency (RF) transmitting circuit with high performance in the BDS-3 terminal. As the key device in an RF transmitting circuit, the RF power amplifier (PA) largely determines the comprehensive performance of the circuit with its transmission power, efficiency, linearity, and integration. Therefore, in this paper, an L-band highly integrated PA chip compatible with 3 W and 5 W output power is designed in InGaP/GaAs heterojunction bipolar transistor (HBT) technology combined with temperature-insensitive adaptive bias technology, class-F harmonic suppression technology, analog pre-distortion technology, temperature-insensitive adaptive power detection technology, and land grid array (LGA) packaging technology. Additionally, three auxiliary platforms are proposed, dedicated to the simulation and optimization of the same type of PA designs. The simulation results show that at the supply voltage of 5 V and 3.5 V, the linear gain of the PA chip reaches 39.4 dB and 38.7 dB, respectively; the output power at 1 dB compression point (P1dB) reaches 37.5 dBm and 35.1 dBm, respectively; the saturated output power (Psat) reaches 38.2 dBm and 36.2 dBm, respectively; the power added efficiency (PAE) reaches 51.7% and 48.2%, respectively; and the higher harmonic suppression ratios are less than −62 dBc and −65 dBc, respectively. The size of the PA chip is only 6 × 4 × 1 mm3. The results also show that the PA chip has high gain, high efficiency, and high linearity under both output power conditions, which has obvious advantages over similar PA chip designs and can meet the short message function of the BDS-3 terminal in various application scenarios. [ABSTRACT FROM AUTHOR]

A very detailed investigation of high-speed silicon–germanium (SiGe) heterojunction bipolar transistors (HBTs) showed an underestimation of the measured peak cutoff frequency by simulations with a hydrodynamic (HD) model. It was speculated that this might be due to a breakdown of the HD approximation or unknown additional mechanical stress. We repeated those simulations with the more fundamental Boltzmann transport equation (BTE) based on the same device model (doping profiles, 2-D geometry, parasitics, and so on) and obtained almost similar results showing that this failure was not due to a breakdown of the HD approximation. Since additional uniaxial stress along the direction of the lateral base has been shown to increase the cutoff frequency, we investigated this effect. We found by 2-D device simulations that the increase in the peak cutoff frequency is rather small, and at high stress levels, it even decreases, if the uniaxial stress is applied homogenously. This is due to the reduction of the conductivity of the highly doped collector layer by the stress. If the stress is limited to the intrinsic transistor, the increase in the cutoff frequency is monotonic with growing stress. On the other hand, the collector current for a given base–emitter voltage also increases with stress leading to an overestimation of the collector current compared with the measurements. If this increase is corrected by a slight decrease in the germanium profile, the gain in the peak cutoff frequency is lost. Thus, the underestimation of the peak cutoff frequency cannot be explained by an additional homogeneous uniaxial stress in the intrinsic transistor. [ABSTRACT FROM AUTHOR]

The effect of InGaAsP and InGaAs cap layers in InP n-p-n heterojunction bipolar transistor (HBT) is presented. The common figures of merit (FOM) in each case are compared to assess their potentials for operation at high frequency. The Gummel-Poon plot of experimental reported result has been used to validate the data obtained from simulation using ATLAS module of Silvaco software tool. After models validation in TCAD tool, the DC and RF characteristics of the HBTs with different cap layers are examined and then a comparative analysis is carried out based on the characteristics such as I–V behaviour, frequency response, minimum noise figure and maximum cut-off frequency. With the change in InGaAs cap to InGaAsP cap, the DC current gain increases from 255 to 300, VCE,offset is reduced from 131 to 76 mV, Early Voltage (VA) increases from −42 to −190 V, cut-off frequency ft is increased from 24.34 MHz to 8.04 GHz, and the maximum oscillation of frequency(fmax) is improves from 13.79 to 37.11 GHz [ABSTRACT FROM AUTHOR]

[Display omitted] • InP Double-Heterojunction Bipolar Transistors (DHBTs) on a 3-inch InP substrate is demonstrated through stepper-based photolithography. • The fabricated DBHTs with W E = 0.6 μm and L E = 15 μm exhibits current gain = 50 at V CE = 1.0 V and an open-base common-emitter breakdown voltage of 5.7 V at J C = 0.01 mA/µm2. • The uniformity of the fabricated DHBT with W E = 0.6 μm and L E = 15 μm shows β = 49.3 ± 1.9, f T = 241.4 ± 3.8 GHz, and f max = 221.5 ± 4.0 GHz, respectively. In this paper, InP Double-Heterojunction Bipolar Transistors (DHBTs) on a 3-inch InP substrate is demonstrated through stepper-based photolithography. The performance of the fabricated InP DHBTs such as DC characteristics, high-frequency characteristics, and uniformity of the 3-inch wafer is investigated to verify the stepper-based fabrication process. To improve the high-frequency characteristics, the self-aligned base-emitter contact is realized by using the high height-to-width ratio and vertical sidewall emitter profile of the Au electroplating process. The fabricated DHBTs with W E = 0.6 μm and L E = 15 μm exhibits current gain (β) = 50 at V CE = 1.0 V and an open-base common-emitter breakdown voltage (BV CEO) of 5.7 V at J C = 0.01 mA/µm2 and 7.5 V at J C = 0.1 mA/µm2, respectively. Moreover, the fabricated DHBTs with W E = 0.6 μm and L E = 15 μm show excellent f T of 244 GHz and f max of 221 GHz at J C = 4.4 mA/μm2 and V CE = 1.6 V. In order to evaluate the uniformity of the fabricated DHBTs, we measure current gain (β) and high-frequency characteristics with W E = 0.6 μm and L E = 15 μm and the average values and standard deviation of the β, f T , and f max are β = 49.3 ± 1.9, f T = 241.4 ± 3.8 GHz, and f max = 221.5 ± 4.0 GHz, respectively. Thanks to the optimized stepper-based fabrication process, the fabricated InP DHBTs exhibit well-balanced high-frequency characteristics and excellent uniformity. [ABSTRACT FROM AUTHOR]

The advantages and the tradeoffs associated with the use of inverse-mode (IM) silicon–germanium (SiGe) heterojunction bipolar transistors (HBTs) biasing circuitry in radio-frequency (RF) voltage-controlled oscillators (VCOs) have been investigated and the performance of proposed VCOs (IM VCOs) is compared with VCOs with conventional forward-mode (FM) SiGe-HBTs (FM VCOs). Where the high-frequency performance of IM VCOs is inevitably degraded due to unfavorable device optimization unlike FM VCOs, IM VCOs provide acceptable low-GHz VCO circuit performance. In terms of single-event effects (SEEs), the IM VCOs show reduced transient peaks and duration in comparison with conventional FM VCOs. In addition, the performance of the VCOs is analyzed in terms of transient error vector magnitude (TEVM) in an RF receiver (RX) using quadrature phase-shift keying (QPSK) modulation under a radiation environment. The IM VCOs in the RX circuit show better reliability under SEEs, offering 28.2% lower TEVM at a 64 Mb/s data rate, than that of the RX circuit with conventional FM VCOs. Therefore, the application of IM SiGe-HBT biasing circuits for RF VCOs can be a viable SEE-hardening technique for space-based RF systems. The VCO prototype was fabricated using IHP 130-nm SiGe bipolar complementary metal-oxide-semiconductor (BiCMOS) technology. [ABSTRACT FROM AUTHOR]

We report a five-gain-stage 150–175-GHz solid-state power amplifier (PA, SSPA) monolithic microwave integrated circuit (MMIC) having modest 20–21-dBm output power $P_{\mathrm {out}}$ , high gain, and high power-added efficiency (PAE). The transistor technology is 250-nm InP HBT. The $S_{21}$ gain is 31.4 ± 1.2 dB from 100 to 178 GHz. The 3-dB $S_{21}$ bandwidth is between 96 and 181 GHz. Typical return loss values for $\vert S_{11}\vert $ and $\vert S_{22}\vert $ exceed 8.5 and 10 dB, respectively. The dc power is 0.72 W. Across 150–175 GHz, the saturated output power $P_{\mathrm {sat}}$ is 106–126 mW with 16–18-dB gain and 12.5%–16.2% PAE—peak values for $P_{\mathrm {out}}$ , gain, and PAE are at 170-GHz operation. The 1-dB gain compression $P_{\mathrm {out}}$ (OP $_{\mathrm {1\,dB}}$) is 30–60 mW. Across the $D$ -band (110–170 GHz), $P_{\mathrm {sat}}$ is 82–126 mW with 9.1%–16.2% PAE. This work establishes a 1.62– $1.89\times $ increase to PAE over 150–175 GHz operation at the output power and gain levels cited. It is also the highest RF output power demonstrated across the full 110–170-GHz WR6.5 waveguide band. [ABSTRACT FROM AUTHOR]

Integrated silicon microwave pin diodes are exposed to 10-keV X-rays up to a dose of 2 Mrad(SiO2) and 14-MeV fast neutrons up to a fluence of $2.2\,\,\boldsymbol {\times }\,\,10\,\,^{\mathrm{ 13}}$ cm−2. Changes in both dc leakage current and small-signal circuit components are examined. Degradation in performance due to total-ionizing dose (TID) is shown to be suppressed by non-quasi-static (NQS) effects during radio frequency (RF) operation. Tolerance to displacement damage from fast neutrons is also observed, which is explained using technology computer-aided design (TCAD) simulations. Overall, the characterized pin diodes are tolerant to cumulative radiation at levels consistent with space applications such as geosynchronous weather satellites. [ABSTRACT FROM AUTHOR]

This brief presents a wideband, low insertion loss, high attenuation range digital step attenuator (DSA) implemented using SiGe HBTs. In a switched-type topology, the off-state capacitances ($\text{C}_{OFF}$) in both reference and attenuation states cause different poles and zeros, which trigger amplitude and phase errors and limit the operating bandwidth. To achieve wide bandwidth, methods to relocate poles and zeros to the highest possible frequencies in both states are investigated. In the reference state, minimizing the size of the shunt switching transistors extends the bandwidth. In the attenuation state, switching in a capacitor at the base of an anti-parallel (AP) SiGe HBT pair series switch reduces the effective $\text{C}_{OFF}$ , enhancing the bandwidth. The proposed techniques facilitate the realization of a 16-dB attenuator cell to support wide bandwidth and offer lower insertion loss than conventional cascaded 8-dB cell designs. Fabricated in 130-nm SiGe BiCMOS technology, the proposed DSA with an attenuation range of 31.5 dB in 0.5 dB steps operates from DC to 67 GHz and achieves an insertion loss lower than 7.8 dB. The RMS amplitude error is less than 0.4 dB above 1 GHz, while the RMS phase variation is less than 13.1°. [ABSTRACT FROM AUTHOR]

This article presents a comprehensive analysis of the terahertz (THz) rectification process with modern high-speed silicon–germanium (SiGe) heterojunction bipolar transistor (HBT) devices to enable low-power and close-to-optimum detector sensitivity in a near-THz fractional bandwidth. The influence of all major device internal parasitics on the detector responsivity and noise equivalent power (NEP) is analyzed in detail as a function of the device bias point and the operating frequency. By analogy to the cold MOSFET operation, the fundamentals of the detector operating in weak and deep saturation are studied and compared with the forward-active region, indicating its potentially superior NEP performance with a suitable readout path. The antenna’s broadband radio frequency (RF) power coupling aspects are further elaborated and related to the device bias conditions to maximize the internal base–emitter driving voltage. A set of single- and dual-polarized antenna-coupled detectors with close-to-optimum detector operation in a near-THz fractional bandwidth and a state-of-the-art optical performance was implemented in a 0.13- $\mu \text{m}$ SiGe HBT technology with $f_{t}/f_{\text {max}}$ of 350/550 GHz and extensively characterized across 200–1000 GHz to support the underlying analysis. For the forward-active operation, the following maximum optical current responsivity and minimum optical NEP values have been demonstrated: 5 A/W, 1.9 pW/ $\sqrt {\text {Hz}}$ at 300 GHz and 0.65 A/W, 19 pW/ $\sqrt {\text {Hz}}$ at 900 GHz. The corresponding NEP values for deep saturation (with unbiased collector) are 5.1 pW/ $\sqrt {\text {Hz}}$ and 45 pW/ $\sqrt {\text {Hz}}$ but they are largely limited by the noise floor of the consecutive external amplifier. [ABSTRACT FROM AUTHOR]

We compare measured and simulated RF third-order distortion current, as well as the corresponding IP3, as a function of bias, for a SiGe heterojunction bipolar transistor (HBT), using MEXTRAM. The collector–base (CB) depletion capacitance model is identified to limit IP3 modeling accuracy near its peak. New CB capacitance modeling options are developed to significantly improve high-current IP3 modeling accuracy, particularly its peak behavior. Guidelines to simultaneous fitting of ƒT, ƒmax, IP3, and CBC are developed. [ABSTRACT FROM AUTHOR]

RF photonic components suffer from poor spurious-free dynamic range (SFDR) due to the high noise and distortion generated by a silicon photonic (SiP) Mach–Zehnder modulator (MZM). This work demonstrates a distributed silicon–germanium (SiGe) heterojunction bipolar transistor (HBT)-based low-noise amplifier (LNA) co-designed for linearization with a SiP MZM for a broadband radio-over-fiber (RoF) link. The SiGe LNA incorporates a distributed, tunable predistortion scheme that is inherently wideband and improves the third-order intercept point over an 18-GHz range. The assembled SiGe LNA and SiP MZM prototype demonstrates an SFDR as high as 120 dB ⋅ Hz2/3 at 9 GHz, a 14-dB improvement over previous SiP RF components or RoF links. [ABSTRACT FROM AUTHOR]

An improved millimeter-wave nonlinear model for InP heterojunction bipolar transistor (HBT) is proposed in this letter. The frequency dispersion effect has been taken into account in the Agilent HBT model in Agilent ADS software. Model verification is carried out by comparison of measured and simulated dc and S-parameters up to 110 GHz. [ABSTRACT FROM AUTHOR]

A 190-GHz mixer-based down-conversion receiver realized in a 130-nm SiGe BiCMOS technology featuring high-speed heterojunction bipolar transistors (HBTs) with ($f_{\text {T}}$ , $f_{\text {max}}$) = (300, 500) GHz is presented. The core part of the receiver consists of a low-noise amplifier (LNA), an active tunable fundamental mixer, an intermediate frequency (IF) buffer amplifier (BA), and an active inverse balun. A wideband, high conversion gain (CG) local oscillator (LO) chain is integrated to make the receiver suitable for applications requiring tunable LO, which contains a multiplier with a multiplication factor of 12 ($\times 12$) and a driver amplifier. To exploit the best possible performance with ultralow dc power consumption ($P_{\text {dc}}$), the mixer and LNA transistors operate at forward-biased base–collector junction voltage ($V_{\text {BC}}$). With a fixed IF frequency at 1 GHz, this receiver exhibits a peak CG of 49 dB with a 14-dB tuning range and a minimum single-sideband noise figure (NF) of 16.5 dB, consuming only 29-mW static dc power for the core part and 171 mW overall, including the LO chain. Within the CG tuning range, this receiver achieves a 6-dB RF bandwidth (BW) from 25 to 32 GHz. Compared with previously reported receivers at similar frequencies, the highest CG and the lowest $P_{\text {dc}}$ with highly competitive performance in terms of BW, CG tuning range, 1-dB output compression point, and NF have been achieved. [ABSTRACT FROM AUTHOR]

This brief presents a low voltage folded-switching ultra-wideband down-conversion mixer in TSMC 0.18 $\mu \text{m}$ SiGe BiCMOS technology. The transconductance stage uses BJT (HBT) transistors to improve the conversion gain. The switching stage uses a CMOS inverter that is switched to reduce the supply voltage and the dc power consumption. The design technology for the mixer combines the advantages of BJT (HBT) and CMOS. The results show a conversion gain of 8.8~ 17.1 dB, ranging from 3 GHz to 11 GHz, a single-ended noise figure from 12.8 dB to 16.56 dB, an input return loss of less than −8 dB and LO-to-RF isolation that is better than −32 dB. The IIP3 is 0 dBm at 3 GHz. The total dc power consumption from a 1V supply voltage with output buffers is 3.45 mW. [ABSTRACT FROM AUTHOR]

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This work focuses on the design issues of radio frequency (RF) bipolar integrated circuits (ICs) as a part of frequency synthesizers for extreme environmental applications. It is shown that silicon–germanium (SiGe) and gallium arsenide (GaAs) heterojunction bipolar transistors (HBTs) as well as bipolar RF ICs (including frequency dividers, voltage-controlled oscillators, and wide-band amplifiers) are highly sensitive to ambient temperature and radiation-induced displacement damage. This article also presents a design approach based on specialized HBT macromodels and hardening techniques. [ABSTRACT FROM AUTHOR]

This letter presents new wideband single-pole double-throw (SPDT) RF switches utilizing SiGe heterojunction bipolar transistors (HBTs) for both series and shunt switches. SiGe HBT, when used as a series switch, exhibits small parasitic components compared to bulk CMOS, which improves insertion loss at high frequency and supports wider bandwidth. For a series switch, three configurations are proposed: using the collector as an input (CI), using the emitter as an input (EI), and using a combination of the two in an antiparallel (AP) fashion. While all three configurations exhibit similar performance, the SPDT switch with the EI SiGe HBT exhibits the best insertion loss and isolation achieving dc-to-above 110-GHz bandwidth, 2.5 dB of insertion loss, and 27.3 dB of isolation at 60 GHz. The SPDT switch with AP SiGe HBT pair exhibits the highest linearity, with 15.6 dBm of input 1-dB compression point (IP 1 dB) at 10 GHz. With 0.61 mW of power dissipation, these new SPDT switches using SiGe HBTs exhibit similar performance to silicon-on-insulator (SOI) CMOS while obtaining higher power capability among conventional series-shunt SPDT designs. [ABSTRACT FROM AUTHOR]

Low-noise amplifiers (LNAs) are necessary components for any communications system. Single-event transients (SETs) induced by energetic particles in space can corrupt the data in an RF receiver. Using p-n-p silicon–germanium (SiGe) heterojunction bipolar transistors (HBTs), instead of their more common n-p-n counterparts, has been shown to be an effective mitigation technique in digital, analog, and RF circuits. Since p-n-p SiGe HBTs tend to have lower performance than n-p-n SiGe HBTs, in this article, the tradeoffs between performance and SET robustness have been evaluated through the use of simulations. Two LNAs were designed using an algorithmic design technique: one using only n-p-n SiGe HBTs, and the other using only p-n-p devices. The n-p-n LNA had higher peak gain and lower noise figure at the center frequency of 5 GHz when compared to the p-n-p LNA, by 3.2 and 0.4 dB, respectively. However, the n-p-n LNA also produced transients with amplitudes larger than the p-n-p LNA across all simulated linear energy transfers. Although the p-n-p LNA has lower overall performance, it is also more robust to SETs. Thus, the choice between using n-p-n and p-n-p SiGe HBTs for an RF design will depend on application requirements. [ABSTRACT FROM AUTHOR]

In this article, a wideband linearization technique for distributed amplifiers (DAs) is presented. In particular, an auxiliary transistor is employed to create additional intermodulation distortion components that will be feed-forwarded to the output of each gain unit cell to significantly suppress the third-order intermodulation (IM3) distortion. To verify the concept, two DAs are fabricated in an indium phosphide (InP) process. One amplifier employs a conventional stacked-heterojunction bipolar transistor (HBT) gain unit cell, and the other linearized amplifier utilizes the proposed technique. The linearized DA exhibits a measured gain of 10.5 dB with a 3-dB gain bandwidth from dc to 90 GHz. The maximum 1-dB gain compression output power ($P_{\text {1 dB}}$) is 20.5 dBm, and the third-order intercept point (OIP3) is 33 dBm. Compared to the conventional amplifier, the two values are improved by 3.5 and 4.5 dB on average, respectively. Moreover, the linearization technique only increases very little dc power consumption at high power and has the same chip size as compared to the conventional design. To the best of the authors’ knowledge, compared to published state-of-the-art DAs, the proposed DA achieves among the highest OIP3 over a wide bandwidth. [ABSTRACT FROM AUTHOR]

The cryogenic performance of radiation-hardened radio-frequency (RF) low-noise amplifiers (LNAs) is presented. The LNA, which was originally proposed for the mitigation of single-event transients (SETs) in a radiation environment, uses inverse-mode silicon-germanium (SiGe) heterojunction bipolar transistors (HBTs) in its core cascode stages. In this prototype, the upper common-base SiGe HBT is configured in inverse mode for balanced RF performance and reduced SET sensitivity. In order to better exploit the inverse-mode LNAs in a variety of extreme-environment applications, the RF performance of the LNA was characterized using liquid nitrogen to evaluate cryogenic operation down to 78 K. While the SiGe LNA exhibits acceptable RF performance for all temperature conditions, there is a noticeable gain drop observed at 78 K compared to the conventional forward-mode design. This is attributed to the limited high-frequency performance of an inverse-mode SiGe HBT. As a guideline, compensation techniques, including layout modifications and profile optimization, are discussed for the mitigation of the observed gain degradation. [ABSTRACT FROM AUTHOR]

In this brief, the design, implementation, and experimental results of an X-band low noise amplifier (LNA) implemented in 0.13 $\boldsymbol \mu \text{m}$ SiGe BiCMOS process technology is reported. The presented LNA based on an inductively degenerated triple-cascode topology employing SiGe hetero-junction bipolar transistors (HBT) featuring ${f} _{\textbf {T}}/{f} _{\textbf {max}}$ of 250/330 GHz. To authors’ best knowledge, this brief is the first LNA incorporating triple-cascode topology and HBTs. Design techniques explored to enhance the gain, noise figure (NF), and linearity performance, along with the investigation of advantages provided by utilizing triple-cascode configuration are addressed. The measurement of the proposed LNA results in a minimum NF of 1.35 dB at 8 GHz, which remains less than 1.7 dB across 6–12 GHz frequency band. In addition, the LNA delivers a peak gain of 20.5 dB at 9 GHz, where it exhibits a state-of-the-art output 1-dB compression point (OP1dB) of 18.75 dBm and third-order intercept point OIP3 of 24.75 dBm, while drawing 21 mA dc current from a 4.8-V supply. According to the utilized figure-of-merit, the measured results are better compared to previously reported work in the open literature. [ABSTRACT FROM AUTHOR]

The benefits of using p-n-p silicon–germanium (SiGe) heterojuction bipolar transistors (HBTs) in radio frequency (RF) circuits for the mitigation of single-event transients (SETs) have been investigated. As a representative circuit example, p-n-p SiGe-HBT RF single-pole single-throw (SPST) switches have been designed in a complementary SiGe BiCMOS platform. The fabricated p-n-p-based RF switches provide comparable RF performance to n-p-n-based switches. In terms of SET transient peaks and duration, the p-n-p SiGe HBT RF switches exhibit a significant reduction in SET sensitivity compared with their n-p-n counterparts. In the frequency domain, the p-n-p switches show fewer low-frequency spurs than that of the n-p-n switches. In addition, inverse-mode p-n-p SiGe HBT switches provide the best overall SET response among all RF SPST switches investigated. [ABSTRACT FROM PUBLISHER]

This paper demonstrates the use of an RF power detector to sense the occurrence of single-event transients (SETs) in RF circuits and systems. The detector was connected to a low-noise amplifier (LNA), and the relationship between the detector output and the LNA transients was investigated via two-photon absorption, pulsed-laser testing, together with mixed-mode TCAD simulations. The response of the detector shows a strong correlation with the RF power of the generated SET. An analytical expression for the detector output is derived and utilized to fit the data. The effects of parameters affecting circuit performance on the detector response to SETs are explored using calibrated TCAD mixed-mode simulations, and design tradeoffs are presented. Finally, a solution to distinguish between transients generated in the detector from those generated in the circuit being monitored is proposed and verified in simulation. The use of detectors to monitor SETs in RF systems could lead to judicious deployment of detection-driven SET mitigation techniques. [ABSTRACT FROM PUBLISHER]

Best practice in mitigation strategies for single-event transients (SETs) in radio-frequency (RF) receiver modules is investigated using a variety of integrated receivers utilizing inverse-mode silicon–germanium (SiGe) heterojunction bipolar transistors (HBTs). The receivers were designed and implemented in a 130-nm SiGe BiCMOS technology platform. In general, RF switches, low-noise amplifiers (LNAs), and downconversion mixers utilizing inverse-mode SiGe HBTs exhibit less susceptibility to SETs than conventional RF designs, in terms of transient peaks and duration, at the cost of RF performance. Under normal RF operation, the SET-hardened switch is mainly effective in peak reduction, while the LNA and the mixer exhibit reductions in transient peaks as well as transient duration. [ABSTRACT FROM PUBLISHER]

The push to conquer the sparsely used electromagnetic spectrum between 100 and 1,000 GHz, commonly known as the millimeter-wave (mmW) and sub-mmW regions, is now in full force. The current rapid development of electronic circuits and subsystems beyond 100 GHz is enabled by improvements in high-frequency semiconductor technology and packaging techniques. In this article, we highlight recent advances we have developed in heterogeneous semiconductor-material chip integration for application toward the mmW frequency bands?in essence, a waferlevel integration approach that replaces chip-to-chip connections with monolithic integration. [ABSTRACT FROM PUBLISHER]

A cascode configuration with inverse-mode (IM) common-emitter silicon-germanium (SiGe) heterojunction bipolar transistors (HBTs) is proposed for the mitigation of single-event transients (SETs) in low-noise amplifiers (LNAs). Conventionally, despite their SET-mitigation capability, IM SiGe HBTs have been considered to be unsuitable for active gain stages due to severe degradation in RF performance. However, with the benefits of aggressive technology scaling, the high frequency performance of IM SiGe HBTs has been significantly improved, thereby enabling them to be utilized in active gain stages with acceptable RF performance. The cascode with IM common-emitter and common-base SiGe HBTs is used for a 2.4 GHz prototype LNA and it achieves adequate RF gain (10 dB) and noise figure (1.9 dB). With regard to SET mitigation, a through-wafer two-photon absorption pulsed-laser experiment is conducted to test the efficacy of this radiation-hardening approach in an advanced 90 nm SiGe BiCMOS platform. The proposed IM-SiGe-HBT-based LNA exhibits 85% reduction in transient peaks compared to the conventional forward-mode cascode LNA. [ABSTRACT FROM PUBLISHER]

For next generation terahertz applications, heterojunction bipolar transistor (HBT) with reduced dimensions and charge plasma (CP) can be a potential candidate due to simplified and inexpensive process. In this paper, a symmetric lateral two-zone SiGe base heterojunction bipolar charge plasma transistor (HBCPT) with an extruded (extended) base is proposed and its performance at circuit level is studied. The linearly graded electric field in the proposed HBCPT provides improved self gain ( β ) and cut-off frequency ( f T ). Two-dimensional (2-D) TCAD and small-signal model based simulations of the proposed HBCPT demonstrates high self gain β 35–172.93 and f T of 1–4 THz for different device parameters. Moreover, f T of 1104.9 GHz and β of 35 can be achieved by decreasing N b up to 8.2 × 10 17 cm − 3 . Although, f T of 2 THz and 4 THz can also be achieved by reducing the base resistance up to 10 Ω and increasing the emitter/collector length up to 63 nm, respectively. The small-signal analysis of common-emitter amplifier based on the proposed HBCPT demonstrate high voltage gain of 50.11 as compared to conventional HBT (18.1). [ABSTRACT FROM AUTHOR]

We report here a compact 140-GHz, 150-mW high-gain solid-state power amplifier (SSPA) monolithic microwave integrated circuit (MMIC) demonstrated in a 250-nm InP HBT technology. It utilizes five-gain stages and two-way on-chip power combining. The amplifier measures 29.5-dB mid-band $S_{21}$ gain and over 125-mW output power across 115–150-GHz operation. The peak 153-mW output power was measured at 140 GHz using only 2.7-mW RF input power—the associated large-signal gain is 17.5 dB with 9.8% power added efficiency (PAE). The 140-GHz OP1 dB 1-dB gain compression power is 106 mW with 7.0% PAE. The dc power dissipation is 1.54 W and its size is only 0.75 mm2. The 3-dB $S_{21}$ gain roll-off is between 112 and 147 GHz. The 115–150-GHz output power variation at 0-dBm input drive is only ±0.5 dB. The peak PAE varies between 8.2% and 10.5%. This D-band result improves upon by $2.3\times $ at 140 GHz the state-of-the-art peak RF power previously demonstrated by SSPA MMICs. [ABSTRACT FROM AUTHOR]

An $E$ -band (71–86-GHz) bidirectional transceiver is presented in this paper. The time-division duplex architecture avoids transmit (TX)/receive (RX) switches through the use of transistor biasing in the signal path to minimize high-frequency loss. The low-noise amplifier (LNA) and power amplifier (PA) are combined into a wideband PA/LNA circuit, which alleviates the parasitic loading of each circuit through a wideband power combiner. The bidirectional transceiver circuit is implemented in 90-nm SiGe BiCMOS process. In TX mode, the bidirectional transceiver transmits a maximum saturated power of 11 dBm at 78 GHz with a 3-dB bandwidth from 71 to 86 GHz. In RX mode, the maximum 30.6-dB conversion gain and the minimum 6.6-dB noise figure are measured at 73 GHz. The whole RF frontend chip consumes 350.2- and 137.7-mW dc power in TX and RX modes, respectively, including all the RF, IF, and local oscillator amplifiers. The overall chip size is 1.5~\text {mm}\times 0.9 mm including pads. [ABSTRACT FROM AUTHOR]

A fast active-quenching circuit (FAQC) based on SiGe Hetero-junction Bipolar Transistor (HBT) and InGaP/GaAs HBT integrated circuits is designed for use with free-running single-photon avalanche diodes (SPADs). The performances of both InGaAsP/InP SPAD and InGaAs/InP SPAD are tested. Results show that the typical avalanche duration using the FAQC is 1.6 ns, and the total afterpulse probability is lower than 10% when the hold-off time is above 1 \mu \texts at 1.5 V excess bias or 10 \mu \texts at 3.0 V excess bias. This result is comparable to recently developed negative-feedback avalanche diodes. The FAQC is based on commercially available integrated circuits and can be used with typical SPADs, providing a low-cost approach to build a free-running single-photon detector. [ABSTRACT FROM PUBLISHER]

The capability of inverse-mode (IM) silicon- germanium (SiGe) heterojunction bipolar transistors (HBTs) for the mitigation of single-event transients (SETs) under large-signal operation was investigated in an RF down-conversion single- balanced mixer using a through-wafer, two-photon absorption pulsed-laser beam experiment and TCAD heavy-ion simulations. The IM SiGe HBTs replace conventional forward-mode (FM) SiGe HBTs in the differential pair, which provides full current steering for frequency mixing operation. Under steady-state conditions, the IM SiGe HBT differential pair exhibits smaller transient peaks with shorter durations compared to the FM SiGe HBTs. In addition, under the injection of a local oscillator (LO) signal with large swing, the IM SiGe HBTs show faster recovery (50% reduction in the best case) from the impact of SETs. In the frequency domain, it is observed that IM SiGe HBTs produce less distortion at the output for an intermediate frequency below 1 GHz. Based on the performance comparison between FM and IM SiGe HBT down-conversion mixers, system design guidelines to compensate the noise figure degradation associated with using IM SiGe HBTs are discussed. [ABSTRACT FROM AUTHOR]

The single-event transient (SET) response of a SiGe-based, L-band low-noise amplifier (LNA) is investigated, with a focus on providing recommendations for radiation event simulation techniques. Pulsed-laser, two-photon absorption experiments show that the SET sensitivity of the SiGe LNA is highly dependent on operating conditions and strike location. Time and frequency-domain analyses raise potential concerns for digital data modulated on RF carrier signals. Device and circuit-level ion-strike TCAD simulations are utilized to compare alternative simulation approaches, highlight the importance of parasitics on SET simulation accuracy, and suggest best practices for modeling radiation-induced transients within RF/mm-wave circuits. [ABSTRACT FROM AUTHOR]

In this letter, an ON–OFF keying (OOK) oscillator that uses a resonant tunneling diode (RTD) pair configuration has been designed and fabricated. To achieve improved RF output power characteristics, the RTD pair topology was utilized in the RTD OOK oscillator design to realize an increased negative differential conductance voltage span. The fabricated IC showed high-speed switching capability of 5 Gb/s with a good phase noise characteristic of −118.17 dBc/Hz at a 1-MHz offset. The maximum RF output power was determined to be −1.76 dBm at a carrier frequency of 24.1 GHz. It consumes 12.5 mW of power, resulting in a good figure of merit value of 2.5 pJ/bit. These results demonstrate its potential as a high-performance ON–OFF mode oscillator for high-data-rate OOK transceiver systems. [ABSTRACT FROM AUTHOR]

Recent improvements in the fabrication technology of InGaAs/InP heterobipolar transistors have enabled highly scaled transistors with power gain bandwidths above 1 THz. Limitations of the conventional fabrication process that reduce RF bandwidth have been identified and mitigated, among which are high resistivity base ohmic contacts, resistive base electrodes, excessive emitter end undercut, and insufficient undercut of large-diameter base posts. A novel two-step deposition process for self-aligned metallization of sub-20-nm bases has been developed and demonstrated. In the first step, a metal stack is directly evaporated onto the base semiconductor without any lithographic processing so as to minimize contamination from resist/developer chemistry. The composite metal stack exploits an ultrathin layer of platinum that controllably reacts with base, yielding low contact resistance, as well as a thick refractory diffusion barrier, which permits stable operation at high current densities and elevated temperatures. Further reduction of overall base access resistance is achieved by passivating base and emitter semiconductor surfaces in a combined atomic layer deposition Al2O3 and plasma-enchanced chemical vapor depositon SiNx sidewall process. This technology enables the deposition of low-sheet-resistivity base electrodes, further improving overall base access resistance and f\textrm {max} bandwidth. Additional process enhancements include the significant reduction of device parasitics by scaling base posts and controlling emitter end and base postundercut. [ABSTRACT FROM AUTHOR]

A novel full D-band (110–170 GHz) multi-mode transconductance down-converter mixer is realized in a 250-nm indium–phosphide double heterojunction bipolar transistor technology. A single-balanced topology is chosen and an active power combiner for the RF and the local oscillator (LO) signals’ combination is used. The designed mixer is feasible to work at \, \times \,1, \, \times \,2, \, \times \,3, \, \times \,4 subharmonically LO-pumped mixing modes with relatively low LO powers of 0, -\1, 5, and 6 dBm, respectively. The measured conversion gain achieves typical values of -\3, -\1, -\5, and -\4 dB over the full D-band while the best noise figures of 12, 13.5, 18.5, and 19 dB are obtained, respectively. Through the multi-mode operation in terms of subharmonic LO-pump-frequency, the designer can make a tradeoff between LO frequency, LO power, and noise figure. [ABSTRACT FROM PUBLISHER]

In this paper, the X-parameter measurements are applied first to establish an improved vertical bipolar inter-company (VBIC) large-signal equivalent-circuit model for silicon–germanium (SiGe) heterojunction bipolar transistors (HBTs), which can accurately describe novel and unusual characteristics of inductive behavior at breakdown that can occur in the active region under large-signal drive. This improved VBIC model presented here for SiGe HBTs is modified by incorporating a nonlinear base–collector junction breakdown network to account for the RF avalanche delay effect in the breakdown region. Good agreement between simulated and measured X-parameters, which contain small-signal S-parameters, large-signal spectrum, and hot S-parameters, is achieved, validating the presented large-signal VBIC model in the breakdown region. The determined breakdown inductance and resistance agree well with the theoretical results. This modified model can be used to describe and predict RF large-signal performance accurately when transistors are operated in the breakdown and active regions. [ABSTRACT FROM PUBLISHER]

This paper investigates the impact of the interconnect between the bottom and the top metal layers on the transistor RF performance of CMOS and silicon–germanium (SiGe) heterojunction bipolar transistor (HBT) technologies. State-of-the-art 32-nm silicon-on-insulator (SOI) CMOS and 120-nm SiGe HBT technologies are analyzed in detail. Measured results indicate a significant reduction in the unity-gain frequency ( fT ) from the bottom to the top metal layer for advanced CMOS technology nodes, but only a slight reduction for SiGe HBTs. The 32-nm SOI CMOS and SiGe HBT technologies have a reduction in the maximum oscillation frequency ( f\textrm {max} ) from the bottom to the top metal layer of $\sim 12$ % and 5%, respectively. By analyzing technology scaling trends, it is clear that SiGe HBTs can now achieve a similar peak fT at the top metal layer in comparison with advanced CMOS technology nodes, and a significantly higher f\textrm {max} . Furthermore, in CMOS technologies, the top metal layer f\textrm {max} appears to have reached a peak around the 45–65-nm technology nodes, a result which has significant implications. [ABSTRACT FROM AUTHOR]

Power versus time (PVT) variation is one of the most important features for describing electrothermal performance of RF power amplifiers (PAs) for global system for mobile communication/digital cellular system bands. The PA sometimes produces high power at the first time slot and low power at the second time slot, which results in similar temperature variation caused by its self-heating effect. Therefore, both theoretical and experimental investigations are carried out for capturing electrothermal effects on the performance of GaAs-based heterojunction bipolar transistor (HBT) PAs. The temperature distribution over the PA die is obtained using our in-house developed finite-element method algorithm and a thermal infrared scanner, respectively. In particular, the PVT variation of the PA for a two time slot, as well as a four time slot (i.e., 75% of its operation time is in the “power on” state) case is studied in detail. Furthermore, an improved design for the GaAs HBT PA chip is performed, fabricated, and tested with its PVT variation suppressed effectively. This study should be very useful for the development of PAs for many wireless communications. [ABSTRACT FROM PUBLISHER]

This paper presents the results of an investigation of the steady-state safe operating conditions for large-signal silicon-germanium (SiGe) heterojunction bipolar transistor (HBT) circuits. By calculating capacitive currents within the intrinsic transistor, avalanche inducing currents through the transistor junctions are isolated and then compared with dc instability points established through simulation and measurement. In addition, calibrated technology computer-aided design simulations are used to provide further insight into the differences between RF and dc operation and stress conditions. The ability to swing the terminals of a SiGe HBT beyond the static $I$ – $V$ conditions coincident with catastrophic breakdown is explained. Furthermore, hot-carrier effects are also compared from multiple perspectives, with supporting data taken from fully realized $X$ -band and $C$ -band cascode driver amplifiers. This analysis provides microwave circuit designers with the framework necessary to better understand the full-voltage-swing potential of a given SiGe HBT technology and the resultant hot carrier damage under RF operation. [ABSTRACT FROM AUTHOR]

This paper presents design and characterization of D-band (110–170 GHz) monolithic microwave integrated quadrature up- and down-converting mixer circuits with on-chip RF and local oscillator (LO) baluns. The circuits are fabricated in 250-nm indium–phosphide double heterojunction bipolar transistor technology. The mixers require an external LO signal and can be used as direct carrier quadrature modulator and demodulator to implement higher order quadrature amplitude modulation formats. The up-converter has a single-sideband (SSB) conversion gain of 6 dB with image and LO suppression of 32 and 27 dBc, respectively. The chip can provide maximum output RF power of 2.5 dBm, a third-order output intercept point of 4 dBm, and consumes 78-mW dc power. The down-converter exhibits 14-dB SSB conversion gain with 25-dB image rejection ratio, and 11.5-dB SSB noise figure. The chip consumes 74-mW dc power and can deliver maximum output IF power of 4 dBm. Both chips have the same size with active area of 560 \mum\,\times\,440 \mum including the RF and LO baluns. [ABSTRACT FROM AUTHOR]

Large-signal (P1dB ) and small-signal (OIP3) radio frequency (RF) linearities of silicon-germanium (SiGe) heterojunction bipolar transistors (HBTs) fabricated in a new fourth-generation 90-nm SiGe BiCMOS technology operating at cryogenic temperatures are investigated. The SiGe BiCMOS process technology has an ƒT/ƒmax of 300/350 GHz. SiGe HBTs with two different layout configurations, collector-base-emitter (CBE) and CBE-base-collector (CBEBC), were characterized over temperature. Both dc and ac figures-of-merit are presented to aid in understanding the linearity, and to provide an overall performance comparison between the two layout configurations. The extracted peak ƒT/ƒmax for CBE and CBEBC at 78 K are 387/350 and 420/410 GHz, respectively. The P1dB and OIP3 linearity metrics for both configurations are comparable. Source- and load-pull measurements were performed at each temperature at 8 and 18 GHz, with the devices biased at a JC of 18 mA/μm2. Two-tone measurements over bias were also performed at 300 and 78 K with 50-Ω terminations for the source and load impedances. The 50 Ω results follow a similar response to the source- and load-pull measurements at 300 and 78 K, and demonstrate that the small-signal linearity of the SiGe HBTs is not adversely impacted by operation at cryogenic temperatures. The CBEBC configuration demonstrated the most consistent RF linearity performance at cryogenic temperature out of the two layout options. [ABSTRACT FROM PUBLISHER]

In this brief, we demonstrate a straightforward approach to obtain isothermal electrical characteristics of state-of-the-art SiGe:C BiCMOS heterojunction bipolar transistors designed for mmWave applications. DC and conventional continuous-wave RF measurements are performed at different chuck temperatures ( Tchuck ). Knowing the thermal resistance ( R TH ) of the device, all the isothermal dc and ac (above thermal cutoff frequency) data can be determined. The validation of the methodology is demonstrated by comparing the results with the pulsed dc and pulsed RF measurements, which are found to be in good agreements. This method could be applied with a standard measurement equipment. [ABSTRACT FROM PUBLISHER]

In this paper, a table-based large-signal model for silicon germanium heterojunction bipolar transistors with the introduction of a breakdown network is presented to describe the avalanche breakdown effect of the base-collector junction on direct current and RF characteristics completely. Input oscillation and output inductive behaviors in the breakdown regime are found to be due to impact ionization induced holes and electrons, respectively. The avalanche breakdown effect and early effect modeled by the breakdown network and output resistance, respectively, can be distinguished in the presented model. In addition, a good agreement between the extracted total input and output resistances at RF and dc is obtained. The validity of this presented large-signal table-based model with multibias intrinsic parameters has been verified through the measured output spectrum and waveform. [ABSTRACT FROM PUBLISHER]

We report a heterogeneously integrated W-band downconverter, consisting of a low noise amplifier (LNA) and a star mixer. An LNA is realized in a 0.1- \mu \textm InP high-electron-mobility transistor (HEMT) technology and features the noise figure of ~2.5 dB and gain ≥25 dB at W-band. Star mixer is realized in four-layer interconnect InP heterojunction bipolar transistor (HBT) and diode process. A novel design eliminates electrically large diode ring by utilizing a multimetal configuration. Mixer chiplet is integrated into the LNA carrier wafer using heterogeneous integration, which offers electrically short connection between two technologies. Heterogeneously integrated interconnect or transition has measured a loss of ~0.8 dB up to 96 GHz. Integrated W-band downconverter has measured the conversion gain ≥0 dB from 87 to 100 GHz. This is a first reported integration of InP HBT chiplets into the InP HEMT wafer using heterogeneous integration, as well as first reported a W-band heterogeneously integrated downconverter. [ABSTRACT FROM PUBLISHER]