63-75 GHz fT SiGe-base heterojunction bipolar technology

Experimental results for maximum cut-off frequency (f
_T
) 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 μm
²
and for current densities as high as 10
⁶
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