Degradation of Si1−<i>x</i>Ge<i>x</i> epitaxial devices by proton irradiation

Abstract

Irradiation damage in n+-Si/p+-Si1−xGex/n-Si epitaxial diodes and heterojunction bipolar transistors by protons is studied. The degradation of the performance increases with increasing proton fluence, whereas it decreases with increasing germanium content and proton energy. The damage coefficient for proton irradiation is nearly the same as for neutron irradiation and is about three orders of magnitude larger than that for electron irradiation. This difference is due to the different number of knock-on atoms and the nonionizing energy loss, which is correlated to the difference of mass and the possibility of nuclear collisions.