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Proton-induced energy deposition in a silicon P-i-N focal plane array is analyzed with Monte Carlo based simulations. These simulations include all physical processes, including events resulting from multiple particles incident on a single pixel, to describe the experimental data accurately. Post-processing of Monte Carlo simulations is done to account for the effects of pile up (multiple hits on a single pixel during one integration time) and non-radiation-induced noise in experiment. The results are compared with experimental data, and demonstrate how direct ionization dominates the cross section, yet fluctuations in dE/dx cause a broad range of energy depositions not addressed by an average LET calculation. An event rate is predicted for a full space proton flux and the dominance of direct ionization is shown and compared to computation using constant LET methods in CREME96. This comparison shows that at lower energies, CREME96 sufficiently predicts the event rate, but at higher energies a high fidelity simulation method is needed to capture the distribution. Index Terms--Energy deposited, event rate, focal plane array, Geant4, Monte Carlo, pile up.

This paper presents a study of the performance degradation in a proton environment of long wavelength infrared (LWIR) HgCdTe detectors. The energy dependence of the Non-Ionizing Energy Loss (NIEL) in HgCdTe provides a framework for estimating the responsivity degradation in LWIR HgCdTe detectors due to on-orbit exposure from protons. Banded detector arrays of different detector designs were irradiated at proton energies of 7, 12, and 63 MeV. These banded detector arrays allowed insight into how the fundamental detector parameters degraded in a proton environment at the three different proton energies. Measured data demonstrated that the detector responsivity degradation at 7 MeV is 5 times larger than the elegradation at 63 MeV. Comparison of the responsivity degraelation at the different proton energies suggests that the atomic Columbic interaction of the protons with the HgCdTe detector is likely the primary mechanism responsible for the degradation in responsivity at proton energies below 30 MeV. Index Terms--HgCdTe detectors, Non-Ionizing Energy Loss (NIEL), proton radiation effects.

This work draws on experimental and simulation results to derive a generalized SEU response model for bulk SiGe HBTs. The model was validated using published heavy ion and new proton data gathered from high-speed HBT digital logic integrated circuits fabricated in the IBM 5AM SiGe BiCMOS process. Calibrating to heavy ion data was sufficient to reproduce the proton data without further adjustment. The validated model is used to calculate upset event rates for low-earth and geosynchronous orbits under typical conditions. Index Terms--Deep trench isolation, Geant4, geosynchronous orbit, low-earth orbit, rate prediction, silicon-germanium HBT, single-event upset.

A comprehensive investigation of the performance dependencies of irradiated SiGe precision voltage reference circuits on 1) total ionizing dose (TID), 2) circuit topology, and 3) radiation source is presented. Two different bandgap voltage references were designed using a first-generation (50-GHz) SiGe BiCMOS technology platform, and subsequently exposed to X-rays at doses of 1080 krad(Si[O.sub.2]) and 5400 krad(Si[O.sub.2]). The degradation in circuit performance following X-ray irradiation depends on both the TID level and the chosen circuit topology. Measurement results show that large TID levels can significantly shift the magnitude of the output voltage. Explanations for the observed shifts are provided by utilizing detailed analyses of the two circuit topologies and considering device-to-circuit interactions. The primary factor responsible for the difference in the circuit response before and after irradiation can be attributed to the excess base leakage current in the SiGe HBT. To investigate the impact of radiation source, the circuit topology showing the worst-case degradation from the X-ray experiment was independently exposed to 63-MeV protons at the same effective TID level. A clear source dependence in the circuit response was observed, and possible origins of this behavior are identified. Index Terms--BiCMOS analog integrated circuits, heterojuction bipolar transistors, ionization damage, proton radiation effects, SiGe, SiGe HBTs, X-rays.

Shift registers featuring radiation-hardening-by-design (RHBD) techniques are realized in IBM 8HP SiGe BiCMOS technology. Both circuit and device-level RHBD techniques are employed to improve the overall SEU immunity of the shift registers. Circuit-level RHBD techniques include dual-interleaving and gated-feedback that achieve SEU mitigation through local latch-level redundancy and correction. In addition, register-level RHBD based on triple-module redundancy (TMR) versions of dual-interleaved and gated-feedback cell shift registers is also realized to gauge the performance improvement offered by TMR. At the device-level, RHBD C-B-E SiGe HBTs with single collector and base contacts and significantly smaller deep trench-enclosed area than standard C-B-E-B-C devices with dual collector and base contacts are used to reduce the upset sensitive area. The SEU performance of these shift registers was then tested using heavy ions and standard bit-error testing methods. The results obtained are compared to the unhardened standard shift register designed with CBEBC SiGe HBTs. The RHBD-enhanced shift registers perform significantly better than the unhardened circuit, with the TMR technique proving very effective in achieving significant SEU immunity. Index Terms--Current mode logic (CML), heavy ion, hetero-junction bipolar transistor (HBT), radiation hardening by design (RHBD), shift register, silicon-germanium (SiGe), single-event upset (SEU), triple-module redundancy (TMR).

We compare, for the first time, the effects of 63 MeV protons on 1st generation and 3rd generation SiGe HBTs irradiated at both liquid nitrogen temperature (77 K) and at room temperature (300 K). The 1st generation SiGe HBTs irradiated at 77 K show less degradation than when irradiated at 300 K. Conversely, the 3rd generation SiGe HBTs exhibits an opposite trend, and the devices irradiated at 77 K show enhanced degradation compared to those irradiated at 300 K. The emitter-base spacer regions for these two SiGe technologies are fundamentally different in construction, and apparently are responsible for the observed differences in temperature-dependent radiation response. At practical circuit biases, both SiGe technology generations show only minimal degradation for both at 77 K and 300 K exposure, to Mrad dose levels, and are thus potentially useful for electronics applications requiring simultaneous cryogenic temperature operation and significant total dose radiation exposure. Index Terms--Interface trapped charge, irradiation, low temperature, proton irradiation, SiGe HBT.

We present, for the first time, an analysis of the error signatures captured during pulsed laser microprobe testing of high-speed digital SiGe logic circuits. 127-bit shift registers, configured using various circuit level latch hardening schemes and incorporated into the circuit for radiation effects self test serve as the primary test vehicle. Our results indicate significant variations in the observed upset rate as a function of strike location and latch architecture. Error information gathered on the sensitive transistor nodes within the latches and characteristic upset durations agree well with recently reported heavy-ion microprobe data. These results support the growing credibility in using pulsed laser testing as a lower-cost alternative to heavy-ion microprobe analysis of sensitive device and circuit nodes, as well as demonstrate the efficiency of the autonomous detection and error approach for high speed bit-error rate testing. Implications for SEU hardening in SiGe are addressed and circuit-level and device-level Radiation Hardening By Design recommendations are made. Index Terms--Built-in self-test, circuit level hardening, high-speed bit-error rate testing, pulsed laser testing, silicon-germanium (SiGe), single-event effects (SEU).

A comprehensive investigation of the effects of proton irradiation on the performance of SiGe BiCMOS precision voltage references intended for extreme environment operational conditions is presented. The voltage reference circuits were designed in two distinct SiGe BiCMOS technology platforms (first generation (50 GHz) and third generation (200 GHz)) in order to investigate the effect of technology scaling. The circuits were irradiated at both room temperature and at 77 K. Measurement results from the experiments indicate that the proton-induced changes in the SiGe bandgap references are minor, even down to cryogenic temperatures, clearly good news for the potential application of SiGe mixed-signal circuits in emerging extreme environments. Index Terms--BiCMOS analog integrated circuits, heterojuction bipolar transistors, proton radiation effects.

We present an investigation of the observed variations in the total dose tolerance of the emitter-base spacer and shallow trench isolation oxides in a commercial 200 GHz SiGe HBT technology. Proton, gamma, and X-ray irradiations at varying dose rates are found to produce drastically different degradation signatures at the various oxide interfaces. Extraction and analysis of the radiation-induced excess base current, as well as low-frequency noise, are used to probe the underlying physical mechanisms. Two-dimensional calibrated device simulations are employed to correlate the observed results to the spatial distributions of carrier recombination in forward- and inverse-mode operation for both pre- and post-irradiation levels. Possible explanations of our observations are offered and the implications for hardness assurance testing are discussed. Index Terms--Dose enhancement, hardness assurance, low-frequency noise, silicon-germanium (SiGe), hetero-junction bipolar transistor, total ionizing dose.

SEE testing at multi-Gbit/s data rates has traditionally involved elaborate high speed test equipment setups for at-speed testing. We demonstrate a generally applicable self test circuit approach implemented in IBM's 5AM SiGe process, and describe its ability to capture complex error signatures during circuit operation at data rates exceeding 5 Gbit/s. Comparisons of data acquired with FPGA control of the CREST ASIC versus conventional bit error rate test equipment validate the approach. In addition, we describe SEE characteristics of the IBM 5AM process implemented in five variations of the D flip-flop based serial register. Heavy ion SEE data acquired at angles follow the traditional RPP-based analysis approach in one case, but deviate by orders on magnitude in others, even though all circuits are implemented in the same 5AM SiGe HBT process. Index Terms--Built in self test, high speed bit error rate testing SiGe, single event effects (SEEs).

The effect of proton irradiation on operating voltage constraints in SiGe HBTs is investigated for the first time in 120 GHz and 200 GHz SiGe HBTs. A variety of operating bias conditions was examined during irradiation, including terminals grounded, terminals floating, and forward active (FA) bias operation. The excess base current degradation at 5.0 x [10.sup.13] p/[cm.sup.2] was similar in all cases. B[V.sub.CEO] and B[V.sub.CBO] showed no significant signs of degradation with irradiation. We also investigated for the first time the impact of radiation on SiGe HBTs biased under so-called 'unstable' conditions (i.e., operating point instabilities). In the case of unstable bias conditions, device degradation under proton exposure is significantly different than for stable bias, and bias conditions can play a significant role in the damage process, potentially raising issues from a hardness assurance perspective. Index Terms--Breakdown voltage, proton irradiation, radiation hardness assurance, SiGe HBTs.

We present the results of gamma irradiation on third-generation, 200 GHz SiGe HBTs. Pre- and post-radiation dc figures-of-merit are used to quantify the tolerance of the raised extrinsic base structure to Co-60 gamma rays for varying device geometries. Additionally, the impact of technology scaling on the observed radiation response is addressed through comparisons to second generation, 120 GHz SiGe HBTs. Comparisons to previous proton-induced degradation results in these 200 GHz SiGe HBTs are also made, and indicate that the STI isolation oxide of the device shows increased degradation following Co-60 irradiation. The EB spacer oxide, on the other hand, demonstrates increased susceptibility to proton damage. Low dose rate proton testing was also performed and indicate that although there is a proton dose rate effect present in these devices, it cannot fully explain the observed trends. Similar trends have previously been observed for buried oxides and isolation oxides in several MOS technologies and have been attributed to increased charge yield in these oxides for 1.2 MeV Co-60 gamma rays when compared to 63 MeV protons. Index Terms--EB spacer, ELDRS, gamma radiation, proton radiation, radiation sources, SiGe, SiGe HBT, shallow trench isolation, technology scaling.

Proton radiation effects in vertical SiGe HBTs fabricated on CMOS-compatible silicon-on-insulator (SOI) are investigated for the first time. Proton irradiation at 63 MeV is found to introduce base leakage current at low base-emitter voltage, delay the onset of Kirk effect at high injection, and increase the frequency response of SiGe HBTs on SOI. The latter two effects are in contrast to those found in conventional bulk SiGe HBTs. Proton irradiation also generates positive fixed oxide and interface charge in the buried oxide, which alters both AI-1 and B[V.sub.CEO] in the SiGe HBT by modulating the electric field in the collector region. Index Terms--HBT, radiation, SiGe, SOI.

We compare heavy ion and proton SEE data on commercial SiGe technologies from IBMs 7 HP and 5 AM processes and Jazz Semiconductors SiGe120 process at data rates from 50 Mb/s to 12.4 Gb/s. Complex burst-error trends correlate with both data rate and particle LET, as well as pulsed laser probing of both data paths and clock distribution circuitry. Index Terms--Ground testing, high-speed testing, silicon germanium (SiGe), single-event effect (SEE), single-event upset (SEU).

We compare measurements and modeling of 27 and 63 MeV proton-induced transients in a large-format HgCdTe long wavelength infrared (LWIR) focal plane assembly operating at 40 K. Charge collection measurements describe very limited diffusion of carriers to multiple pixels showing significantly reduced particle induced cross-talk for the lateral diffusion structure. Index Terms--Infrared detectors, protons, radiation effects.

Photonic imagers are being increasingly used in space systems, where they are exposed to the space radiation environment. Unique properties of these devices require special considerations for radiation effects. This paper summarizes the evolution of radiation effects understanding in infrared detector technology, charge coupled devices, and active pixel sensors. The paper provides a discussion of key radiation effects developments and a view of the future of the technologies from a radiation effects perspective. Index Terms--Active pixel sensor (APS), charge-coupled device (CCD), displacement damage, IR detectors, photonic imagers, total dose.

This paper provides a historical review of the literature on the effects of radiation-induced displacement damage in semiconductor materials and devices. Emphasis is placed on effects in technologically important bulk silicon and silicon devices. The primary goals are to provide a guide to displacement damage literature, to offer critical comments regarding that literature in an attempt to identify key findings, to describe how the understanding of displacement damage mechanisms and effects has evolved, and to note current trends. Selected tutorial elements are included as an aid to presenting the review information more clearly and to provide a frame of reference for the terminology used. The primary approach employed is to present information qualitatively while leaving quantitative details to the cited references. A bibliography of key displacement-damage information sources is also provided. Index Terms--Annealing, damage correlation, defects, displacement damage, nonionizing energy loss, radiation effects, semiconductors, silicon, silicon devices.

This paper investigates the impact of proton irradiation on the 1/f noise in ultra-high-voltage chemical-vapor deposition SiGe heterojunction bipolar transistors. The relative degradation of 1/f noise shows a strong dependence on device geometry. Both the geometry dependence and the bias dependence of 1/f noise change significantly after exposure to 2 x [10.sup.13] p/[cm.sup.2] protons. An expression describing the 1/f noise is derived and used to explain the experimental observations. Index Terms--1/f noise, proton irradiation, SiGe heterojunction bipolar transistor (HBT).

The effects of 63-MeV proton irradiation on SiGe: C heterojunction bipolar transistors (HBTs) are reported for the first time. The dc characteristics and neutral base recombination of these SiGe: C HBTs are investigated for proton fluences up to 5 x [10.sup.13] p/[cm.sup.2]. A comparison is made with SiGe HBTs fabricated in the same technology. Despite the fact that these SiGe: C HBTs degrade significantly during proton exposure, there is no indication that the carbon doping has any significant impact on the radiation response. Index Terms--Neutral base recombination, proton irradiation, SiGe: C heterojunction bipolar transistor (HBTs).

Assessing the risk of using optocouplers in satellite applications offers challenges that incorporate those of commercial off-the-shelf devices compounded by hybrid module construction techniques. We discuss approaches for estimating this risk. In the process, we benchmark our estimates for proton and heavy-ion induced single-event transient rate estimates with recent flight data from the Terra mission. For parametric degradation, we discuss a method for acquiring test data and mapping it into an estimation approach that captures all the important variables of circuit application, environment, damage energy dependence, complex response to total ionizing dose and displacement effects, temperature, and annealing. Index Terms--Displacement damage, hardness assurance, optocouplers, single-event effects (SEEs), total ionizing dose.

We investigate the proton tolerance of fully depleted silicon-on-insulator (SOI) MOSFETs with H-gate and regular-gate structural configurations. For the front-gate characteristics, the H-gate does not show the edge leakage observed in the regular-gate transistor. An anomalous kink in the back-gate linear [I.sub.D]-[V.sub.GS] characteristics of the fully depleted SOI nFETs has been observed at high radiation doses. This kink is attributed to charged traps generated in the bandgap at the buried oxide/silicon film interface during irradiation. Extensive two-dimensional simulations with MEDICI were used to understand the physical origin of this kink. We also report unusual self-annealing effects in the devices when they are cooled to liquid nitrogen temperature. Index Terms--Fully depleted, H-gate, kink, proton, radiation, self-annealing, SIMOX, SOI MOSFETs.

This paper presents single-event effect (SEE) modeling results of circuit-hardened SiGe heterojunction bipolar transistor logic circuits. A simple equivalent circuit is proposed to model the ion-induced currents at all of the terminals, including the p-type substrate. The SEE sensitivity of a D-flip-flop was simulated using the proposed equivalent circuit. The simulation results are qualitatively consistent with earlier SEE testing results. The circuit upset is shown to be independent of the number of active paths. Considerable charge collection occurs through the reverse-biased n-collector/p-substrate junction, regardless of the status of the emitter steering current, resulting in circuit upset through the commonly connected load resistor. A heavily doped substrate is shown to be beneficial for SEE. Index Terms--Charge collection, circuit modeling, current-mode logic, heterojunction bipolar transistor (HBT), SiGe, single-event effects (SEEs).

We present a comparison of proton single event ground test results for two generations of MIL-STD-1773 fiber optic data bus interface modules. Single event upset rate prediction techniques for fiber optic data systems are also demonstrated and compared with in-flight space performance.

We present data on recent optocoupler in-flight anomalies and the subsequent ground test irradiation performed. Discussions of the single event mechanisms involved, transient filtering analysis, and design implications are included. Proton-induced transients were observed on higher speed optocouplers with a unique dependence on the incidence particle angle. The results indicate that both direct ionization and nuclear reaction-related mechanisms are responsible for the single events observed.

We present the first experimental results of the effects of 63 MeV proton irradiation on both the lateral and vertical scaling properties of SiGe HBT BiCMOS technology. Three distinct generations of (unhardened) SiGe technology are examined. The first generation SiGe HBTs experience very minor degradation in current gain at proton fluence as high as 2 x [10.sup.13] p/[cm.sup.2]. The second and third generations SiGe HBTs, however, show 60-70% degradation in current gain under similar conditions, suggesting that emitter-base spacer optimization may be required as the technology is scaled. Si nFETs from the first generation SiGe BiCMOS technology are only hard to about 40 krad equivalent gamma dose, and are limited by drain-to-source leakage along the shallow trench edge. The second generation Si nFETs, however, improve with scaling since the shallow trench is thinned, and can withstand up to 150 krad of equivalent dose.

We measure the energy dependence of proton-induced LED degradation using large numbers of devices and incremental exposures to gain high confidence in the proton energy dependence and device-to-device variability of damage. We compare single versus double heterojunction AlGaAs technologies (emitting at 880 nm and 830 nm, respectively) to previous experimental and theoretical results. We also present a critical review of the use of nonionizing energy loss in AlGaAs for predictions of on-orbit degradation and assess the uncertainties inherent in this approach.