Mdr. Hashim et al., EFFECT OF TRANSISTOR GEOMETRY ON THE ELECTRICAL CHARACTERISTICS OF SI1-XGEX HETEROJUNCTION BIPOLAR-TRANSISTORS AT LOW-TEMPERATURES, Journal de physique. IV, 6(C3), 1996, pp. 119-124
This paper investigates the effect of using an extrinsic implant on th
e behaviour of SiGe HBTs at low temperatures. The collector current ch
aracteristics of SiGe HBTs with different geometries are measured at t
emperatures from 77 to 300K. The temperature dependence of the collect
or current is different for devices with different geometries and this
results from base profile broadening in the vicinity of the extrinsic
base implant due to point defects. Process and device simulators are
used to explain this effect. A method for eliminating this geometry de
pendence of the collector current is also described.