63-75 GHz f_T SiGe-base heterojunction bipolar technology

Abstract

Experimental results for maximum cut-off frequency (fT) values of 75 and 52 GHz were achieved for SiGe-base and Si-base bipolar transistors with intrinsic base sheet resistances in the 10-17 kΩ/square range. These results extend the speed of silicon bipolar devices into a regime previously reserved to GaAs and other compound semiconductor technologies. Excellent junction characteristics were also obtained for devices as large as 100000 μm2 and for current densities as high as 106 A/cm 2. The performance levels obtained for the SiGe transistors, which contain less than 10% germanium in the base, represent almost a factor of two increase in the speed of a Si bipolar transistor. These results demonstrate the significant performance advantage offered by SiGe heterojunction technology. © 1990 IEEE.