EFFECT OF RADIATION SOURCE ON THE DEGRADATION IN IRRADIATED SI1-XGEX EPITAXIAL DEVICES

Irradiation damage in n(+)-Si/p(+)-Si1-xGex epitaxial diodes and n(+)- Si/p(+)-Si1-xGex/n-Si epitaxial heterojunction bipolar transistors (HB Ts) is studied as a function of germanium content, radiation source, a nd fluence. The degradation of electrical performance of the devices b y irradiation increases with increasing fluence, while it decreases wi th increasing germanium content. The induced lattice defects ii the Si 1-xGex epitaxial layer and Si substrate are studied by DLTS methods. I n the Si1-xGex epitaxial layer of diodes and HBTs, all electron captur e level which is associated with interstitial boron is; induced by irr adiation, while electron capture levels corresponding to E center and divacancy are formed in the collector region for HBTs. The impact of t ile radiation source on the degradation of performance is correlated w ith simulations of the number of knock-on atoms and the nonionizing en ergy loss (NIEL).