Radiation damage in Si1-xGex heteroepitaxial devices

Results are presented of an extended study on the induced lattice defects a nd their effects on the degradation of Si1-xGex devices, subjected to a 20 MeV alpha-ray, 1 MeV electron, 1 MeV fast neutron, and 20 and 86 MeV proton irradiations. The degradation of the electrical device performance increas es with increasing fluence, while it decreases with increasing germanium co ntent. In the Si1-xGex epitaxial layers. electron capture levels associated with an interstitial-substitutional boron complex are induced. The radiati on source dependence of performance degradation is attributed to the differ ence of mass and the probability of nuclear collision for the formation of lattice defects.