Polycrystal isolation of InGaP/GaAs HBTs to reduce collector capacitance

Author

Mochizuki, K. ; Ouchi, K. ; Hirata, Kazufumi ; Tanoue, T. ; Oka, T. ; Masuda, H.

Author_Institution

Central Res. Lab., Hitachi Ltd., Tokyo, Japan

Volume

19

Issue

2

fYear

1998

Firstpage

47

Lastpage

49

Abstract

InGaP/GaAs heterojunction bipolar transistors (HBTs) with polycrystalline GaAs buried under the base electrode have been fabricated using low-temperature gas-source molecular beam epitaxy on SiO₂-patterned substrates. A cutoff frequency of 120 GHz and a maximum oscillation frequency of 230 GHz were obtained for three parallel 0.7×8.5 μm HBTs. Compared to HBTs without the polycrystal, the collector capacitance was reduced by 28% and the maximum stable gain was improved by 1.2 dB due to complete carrier depletion in the polycrystal under the base electrode. These results show the high potential of the proposed HBTs for high-speed digital and broadband-amplifier applications.

Keywords

III-V semiconductors; buried layers; capacitance; chemical beam epitaxial growth; gallium arsenide; gallium compounds; heterojunction bipolar transistors; indium compounds; isolation technology; millimetre wave bipolar transistors; semiconductor growth; 0.7 mum; 120 GHz; 230 GHz; 8.5 mum; GaAs; InGaP-GaAs; InGaP/GaAs HBTs; SiO/sub 2/-GaAs; SiO/sub 2/-patterned substrates; base electrode; broadband-amplifier applications; buried polycrystalline GaAs; collector capacitance reduction; complete carrier depletion; cutoff frequency; high-speed digital applications; low-temperature gas-source molecular beam epitaxy; maximum oscillation frequency; maximum stable gain; polycrystal isolation; Bipolar transistors; Capacitance; Cutoff frequency; Doping; Electrodes; Gallium arsenide; Gold; Heterojunction bipolar transistors; Molecular beam epitaxial growth; Substrates;

fLanguage

English

Journal_Title

Electron Device Letters, IEEE

Publisher

ieee

ISSN

0741-3106

Type

jour

DOI

10.1109/55.658599

Filename

658599