Frequency increase of an InP-based HBT using improved layout design and base-collector undercut process

摘要

In this article, an improved layout design and a base-collector undercut etching process have been proposed and demonstrated for a high-speed InP/InGaAs heterojunction bipolar transistor (HBT). The fabricated HBT using proposed methods has a smaller parasitic base-collector (B-C) area, resulting in reduced B-C capacitance (C-BC), a reduction of 36% compared to that in the conventional HBT. A current gain cutoff frequency (f(T)) and a maximum oscillation frequency (f(max)) of the proposed HBT have been increased from 110 to 131 GHz and from 112 to 131 GHz due to the reduced C-BC. These results clearly show the effectiveness of the proposed technique for the HBTs.