A 40 GHz f/sub T/ Si bipolar transistor LSI technology

A high-speed Si bipolar transistor with f/sub T/ (cutoff frequency) of 40 GHz using advanced BSA (BSG self-aligned) technology is described. The advanced BSA technology is characterized by graded profiled collector, buried emitter electrode structure, and 0.8- mu m design rule. The advanced BSA technology for further improving the f/sub T/ performance of the sub-100-nm-deep base transistor has been developed by adding these three technologies to the basic BSA technology, in which chemical vapor deposition (CVD)-BSG film is used as a diffusion source to form the intrinsic base and the p/sup +/-link region and as a sidewall spacer between emitter polysilicon and base polysilicon electrodes. The optimized transistor using the advanced BSA technology has exhibited a cutoff frequency of 38 GHz at V/sub CE/ of 1 V, and ECL (emitter coupled logic) gate delay time of 29 ps at I/sub CS/ of 0.3 mA.<>