Operation of SiGe bipolar technology at cryogenic temperatures

Cressler, John D.

doi:10.1051/jp4:1994616

Cited by 10 publications

(3 citation statements)

References 5 publications

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“…An HBT is a type of bipolar junction transistor that uses different semiconductor materials for the emitter and base regions. Among the available technologies, Silicon Germanium (SiGe) HBTs, which are manufactured by many foundries for high bandwidth applications, are particularly well-suited for cryogenic operation because of their bandgap-engineered base [4].…”

Section: Lmh6629 Characterizationmentioning

confidence: 99%

Development of a Very Low-Noise Cryogenic Preamplifier for Large-Area SiPM Devices

D’Incecco

Galbiati

Giovanetti

et al. 2018

IEEE Trans. Nucl. Sci.

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Silicon Photomultipliers (SiPMs) are an excellent candidate for the development of large-area light sensors. Large SiPM-based detectors require low-noise preamplifiers to maximize the signal coupling between the sensor and the readout electronics. This article reports on the development of a low-noise transimpedance amplifier sensitive to single-photon signals at cryogenic temperature. The amplifier is used to readout a 1 cm 2 SiPM with a signal to noise ratio in excess of 40.

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Section: Lmh6629 Characterizationmentioning

confidence: 99%

Development of a Very Low-Noise Cryogenic Preamplifier for Large-Area SiPM Devices

D’Incecco

Galbiati

Giovanetti

et al. 2018

IEEE Trans. Nucl. Sci.

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“…Parallel with these developments in high-speed technology, there has also been interest in the development of BiCMOS processes for operation at liquid nitrogen temperature [7], [8]. The well known difficulty with the low-temperature operation of bipolar transistors is the exponential decrease in current gain with decreasing temperature.…”

Section: Introductionmentioning

confidence: 99%

Determination of bandgap narrowing and parasitic energy barriers in SiGe HBT's integrated in a bipolar technology

Tron

Hashim

Ashburn

et al. 1997

IEEE Trans. Electron Devices

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Abstract-This paper describes a method for characterizing the bandgap narrowing and parasitic energy barrier in SiGe heterojunction bipolar transistors (HBT's), fabricated using a singlepolysilicon self-aligned bipolar process. From a comprehensive study of the temperature dependence of the collector current, the bandgap narrowing in the base due to germanium has been dissociated from that due to the heavy dopant concentration. The same approach has been used to characterize the height and width of parasitic energy barriers which appear when boron out-diffusion from the SiGe base is present. The method has been applied to SiGe heterojunction bipolar transistors fabricated using a single polysilicon, self aligned, bipolar process, as well as mesa transistors. The experimental results show that small geometry transistors have degraded collector currents due to boron out-diffusion around the perimeter of the emitter. This behavior has been explained by accelerated boron diffusion due to point defect generated during the extrinsic base implant. The values of undoped SiGe spacer thickness needed to suppress the parasitic energy barrier are described. Finally, high-frequency results are reported, which correlate the frequency transition to these parasitic energy barriers.

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“…Parameters q and y represent the ratio of position-averaged minority carrier mobility in the base region of a SiGe HBT compared to that in a Si BJT, and the ratio of position-averaged density-of-states in the base region of a SiGe HBT compared to that in a Si BJT, respectively. Equations (1) and (2) indicate that both Vq and pVr\ in SiGe HBTs can be improved by increasing the bandgap grading in the base region. It is also clear that by cooling, an exponential increase in both of these parameters can be obtained for a SiGe HBT when compared to a similarly constructed Si BJT.…”

Section: Introductionmentioning

confidence: 99%

Optimization of Early Voltage for Cooled SiGe HBT Precision Current Sources

1996

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Abstract:The influence of Ge profile shape on the temperature characteristics of two key analog transistor parameters, Early voltage (VA) and current gain-Early voltage product (PVA), in SiGe HBTs have been studied over the temperature range of 300K-77K using SCORPIO, a transistor simulation tool calibrated to measured data [I]. A new version of SPICE that accounts for the temperature dependence of V, was used to model the various SiGe HBTs simulated and thereby evaluate the cryogenic performance of SiGe HBT precision current sources, which are strongly influenced by the variations in both P and VA. Results clearly indicate that the cryogenic performance of these SiGe current sources can be significantly improved by using a graded Ge profile instead of a constant Ge profile in the base region of the HBT.

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Operation of SiGe bipolar technology at cryogenic temperatures

Cited by 10 publications

References 5 publications

Development of a Very Low-Noise Cryogenic Preamplifier for Large-Area SiPM Devices

Development of a Very Low-Noise Cryogenic Preamplifier for Large-Area SiPM Devices

Determination of bandgap narrowing and parasitic energy barriers in SiGe HBT's integrated in a bipolar technology

Optimization of Early Voltage for Cooled SiGe HBT Precision Current Sources

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