A study of the interaction of electron beam generated excess charge-carriers with a Si/SiGe/Si heterostructure

The recombination properties of a Si/SiGe/Si double heterostructure have been investigated by means of the electron beam induced current (EBIC) technique. Measurements of the EBIC collection efficiency dependence on electron beam energy and current have been performed at room temperature. The results are fitted by a simple model in which the SiGe epilayer is approximated by a single interface of finite recombination velocity. Interpretation of the results in terms of the Shockley-ReadHall recombination model, and taking into account the influence of the excess carrier density, suggest the following parameters characterizing the SiGe/Si interface: a deep level located near mid-gap with a ratio of capture cross-sections of holes and electrons around 5 and an areal density of centres around 5 × 1013 cm−2.