Title :
Small-scaled InGaP/GaAs HBTs with WSi/Ti base electrode and buried SiO2
Author :
Oka, Tohru ; Hirata, Koji ; Ouchi, Kiyoshi ; Uchiyama, Hiroyuki ; Mochizuki, Kazuhiro ; Nakamura, T.
Author_Institution :
Central Res. Lab., Hitachi Ltd., Tokyo, Japan
fDate :
11/1/1998 12:00:00 AM
Abstract :
This paper describes the fabrication and characteristics of small-scaled InGaP/GaAs HBTs with high-speed as well as low-current operation. To reduce both the emitter size SE and the base-collector capacitance CBC simultaneously, the HBTs are fabricated by using WSi/Ti as the base electrode and by burying SiO2 in the extrinsic base-collector region under the base electrode. WSi/Ti simplifies and facilitates processing to fabricate a small base electrode, and makes it possible to reduce the width of the base contact to less than 0.4 μm without the large increase in the base resistance. The DC current gain of 20 is obtained for an HBT with S E of 0.3×1.6 μm2 due to the suppression of emitter size effect by using InGaP as the emitter material. An HBT with SE of 0.6×4.6 μm2 exhibited fT of 138 GHz and fmax of 275 GHz at IC of 4 mA; and an HBT with SE of 0.3×1.6 μm2 exhibited fT of 96 GHz and fmax of 197 GHz at IC of 1 mA. These results indicate the great potential of these HBTs for high-speed and low-power circuit applications
Keywords :
III-V semiconductors; capacitance; gallium arsenide; heterojunction bipolar transistors; indium compounds; semiconductor device metallisation; titanium; tungsten compounds; 0.3 micron; 0.6 micron; 1 mA; 1.6 micron; 138 GHz; 197 GHz; 275 GHz; 4 mA; 4.6 micron; 96 GHz; DC current gain; III-V semiconductors; WSi-Ti-InGaP-GaAs; base electrode; base-collector capacitance; emitter size; emitter size effect; extrinsic base-collector region; high-speed operation; low-current operation; small-scaled HBTs; Circuits; Contact resistance; Cutoff frequency; Dielectric constant; Electrodes; Fabrication; Gallium arsenide; Gallium compounds; Heterojunction bipolar transistors; Parasitic capacitance;
Journal_Title :
Electron Devices, IEEE Transactions on
