Growth mechanism of an aluminium-induced solid phase epitaxial (AI-SPE) Si0.5Ge0.5 layer using in situ heating transmission electron microscopy

Abstract

The mechanism of growth of an epitaxial Si_0.5Ge_0.5 layer on a single crystalline (sc) Si (100) substrate by aluminum-induced solid phase epitaxy (AI-SPE) at a relatively low temperature (450 °C) has been revealed using in situ heating transmission electron microscopy (TEM). The analysis of the thermodynamics exactly supports the finding from in situ TEM. It evidences that the Si_0.5Ge_0.5 prefers to nucleate at the interface of the Al layer and the sc-Si (100) substrate due to the lowest critical thickness for nucleation. Based on the results from in situ TEM and thermodynamic analysis, the germanium (Ge) virtual substrate of the compositional gradient can be successfully prepared via a multi-run AI-SPE process at low-temperature.