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Proceedings Paper

Microwave noise characteristics of GaAs-based HBTs
Author(s): Hidenori Shimawaki; Masafumi Kawanaka; Norio Goto
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Paper Abstract

Based on the design guidelines for low-noise HBTs which is derived from Hawkins' model, an AlGaAs/GaAs HBT with emitter-ledge passivation is fabricated for low frequency applications. This HBT increases the current gain, especially at low collector current densities--a key device parameter that impacts the noise figure at low frequencies. An NFmin of 0.6 dB with an Ga of 17.7 dB is obtained for an HBT with 2.5- X 20-micrometers X 2 emitters at 2 GHz. An AlGaAs/InGaAs HBT with regrown base contacts is also fabricated to reduce the base transit time and the base resistance, without increasing the emitter junction capacitance, for higher frequency low-noise applications. This HBT achieves an NFmin of 1.2 dB with a Ga of 10.3 dB and an NFmin of 1.7 dB with a Ga of 8.7 dB at 12 and 8 GHz, respectively, and can be useful at low frequencies as well, due to a low equivalent noise resistance that make noise matching easier.

Paper Details

Date Published: 13 December 1999
PDF: 9 pages
Proc. SPIE 3861, Gigahertz Devices and Systems, (13 December 1999); doi: 10.1117/12.373007
Show Author Affiliations
Hidenori Shimawaki, NEC Corp. (Japan)
Masafumi Kawanaka, NEC Corp. (Japan)
Norio Goto, NEC Corp. (Japan)

Published in SPIE Proceedings Vol. 3861:
Gigahertz Devices and Systems
Dwight C. Streit, Editor(s)

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