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The implementation of a "superjunction" collector design in a silicon--germaniumheterojunction bipolar transistor technology is explored for enhancing breakdown performance. The superjunction collector is formed via the placement of a series of alternating the p/xn-doped layers in the collector-base space charge region and is used to reduce avalanche generation leading to breakdown. An overview of the physics underlying superjunction collector operation is presented, together with TCAD simulations, and a parameterization methodology is developed to explore the limits of the superjunction collector performance. Measured data demonstrate the limitations explored in simulation. [ABSTRACT FROM AUTHOR]

We present the first measurement results of a highly scaled, 90-nm silicon–germanium heterojunction bipolar transistor (SiGe HBT) operating at cryogenic temperatures as low as 70 mK. The SiGe HBT exhibits a transistor-like behavior down to 70 mK, but below 40 K, the transconductance suggests the presence of non-equilibrium transport mechanisms. Despite the non-ideal base current at cryogenic temperatures, a $dc$ current gain (\beta) > 1$ is achieved for I_{C} > 1 nA, suggesting that ultra-low-power low-noise amplifiers should be viable. Exposure of the SiGe HBT to strong magnetic fields (±14 T) is also presented to help understand the nature of the non-ideal current. [ABSTRACT FROM PUBLISHER]

A physics-based silicon-germanium (SiGe) heterojunction bipolar transistor (HBT) aging model for mixed-mode stress based on the lucky-electron model and reaction-diffusion theory is developed for integration with compact models. An effective aging parameter extraction method is described, and the aging model parameters are fit for a modern SiGe HBT platform. The aging model is implemented as a wrapper in the Cadence Spectre circuit simulator. Device-level aging simulations are shown to be well-matched to measured degradation data. The aging model is further used to explore the effects of aging on a simple current mirror circuit, showing a decrease in mirror ratio with degradation. [ABSTRACT FROM PUBLISHER]

The effects of negative feedback, both external and internal, on single event transients (SETs) in SiGe HBT analog circuits are investigated. In order to examine internal negative feedback effects, basic common-emitter NPN current mirrors, with and without emitter degeneration resistors, are utilized. A Wilson current mirror and a Wilson mirror with its intrinsic external feedback removed are used to study external negative feedback effects under the influence of laser-induced single events. The measurement data clearly show notable improvements in SET response that can be made by employing both internal and external negative feedback. The peak transient in the output current is reduced, and the settling time upon a laser strike is shortened significantly by negative feedback. All four investigated current mirrors were fabricated with IBM 8HP 130 nm SiGe BiCMOS technology. [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]

We demonstrate record ac performance (0.8 THz) for a silicon-germanium heterojunction bipolar transistor (SiGe HBT) operating at cryogenic temperatures. An extracted peak fMAX of 798 GHz (peak fT of 479 GHz) at 4.3 K was measured for a device with a BVCEO of 1.67 V. This scaled SiGe HBT also exhibits excellent thermal properties, as required from an electro-thermal reliability perspective. Taken together, these results strongly suggest that at the limits of scaling, robust, and manufacturable SiGe HBTs designed for room temperature operation are likely to achieve THz speeds. [ABSTRACT FROM PUBLISHER]