Quasiballistic electron transport in cryogenic SiGe HBTs studied using an exact, semi-analytic solution to the Boltzmann equation
- Creators
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Naik, Nachiket R.
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Minnich, Austin J.
Abstract
Silicon–germanium heterojunction bipolar transistors (HBTs) are of interest as low-noise microwave amplifiers due to their competitive noise performance and low cost relative to III–V devices. The fundamental noise performance limits of HBTs are thus of interest, and several studies report that quasiballistic electron transport across the base is a mechanism leading to cryogenic non-ideal IV characteristics that affect these limits. However, this conclusion has not been rigorously tested against theoretical predictions because prior studies modeled electron transport with empirical approaches or approximate solutions of the Boltzmann equation. Here, we study non-diffusive transport in narrow-base SiGe HBTs using an exact, semi-analytic solution of the Boltzmann equation based on an asymptotic expansion approach. We find that the computed transport characteristics are inconsistent with experiments, implying that quasiballistic electron transport is unlikely to be the origin of cryogenic non-ideal IV characteristics. Our work helps to identify the mechanisms governing the lower limits of the microwave noise figure of cryogenic HBT amplifiers.
Additional Information
© 2021 Published under an exclusive license by AIP Publishing. Submitted: 12 July 2021; Accepted: 29 September 2021; Published Online: 1 November 2021. The authors thank Mark Lundstrom, J. P. Peraud, and Nicolas Hadjiconstantinou for useful discussions. This work was supported by the National Science Foundation (NSF) (Award No. 1911926). The authors have no conflicts to disclose. Data Availability: The data that support the findings of this study are available from the corresponding author upon reasonable request.Attached Files
Published - 174504_1_online.pdf
Submitted - 2106-05374.pdf
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Additional details
- Eprint ID
- 109794
- Resolver ID
- CaltechAUTHORS:20210713-213714240
- NSF
- ECCS-1911926
- Created
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2021-07-13Created from EPrint's datestamp field
- Updated
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2023-10-03Created from EPrint's last_modified field