A self-aligned SiGe base bipolar technology using cold wall UHV/CVD and its application to optical communication ICs

A self-aligned SiGe base bipolar technology and its application to optical communication ICs are presented. Using cold wall ultra-high vacuum (UHV)/CVD technology, a self-aligned selective SiGe/Si epitaxial growth can be realized for the overhanging structure of the base electrode polysilicon. This is a novel self-aligned bipolar transistor, which we call a super self-aligned selectively grown SiGe base (SSSB) bipolar transistor. The maximum cut-off frequency f/sub T/ of 60 GHz and the maximum frequency of operation f/sub max/ of 50 GHz have been obtained. This technology has been applied to optical communication ICs. A receiver and a transmitter ICs fabricated on a silicon on insulator (SOI) substrate stably operate at up to 20 Gb/s.