GERMANIUM CONTENT DEPENDENCE OF RADIATION-DAMAGE IN STRAINED SI1-XGEXEPITAXIAL DEVICES

The irradiation damage in n(+)-Si/p(+)-Si1-xGex epitaxial diodes and n (+)-Si/p(+)-Si1-xGex/n-Si epitaxial heterojunction bipolar transistors (HBTs) by fast neutrons and MeV electrons is studied as a function of fluence and germanium content for the first time. The degradation of the electrical performance of both diodes and HBTs by irradiation incr eases with increasing fluence, while it decreases with increasing germ anium content. The damage coefficient of reverse current for x = 0.12 and 0.16 diodes irradiated by neutrons is calculated to be 6.2 x 10(-2 1) and 5.5 x 10(-21) n(-1)Acm(2), respectively. That of h(FE) for elec tron-irradiated x = 0.08, 0.12 and 0.16 HBTs is 7.6 x 10(-16), 2.7 x 1 0(-16) and 1.6 x 10(-16) e(-1)cm(2), respectively.