Ellipsometry studies of Si/Ge superlattices with embedded Ge dots

Abstract

In this paper, we present an analysis for treating the spectroscopic ellipsometry response of Si/Ge superlattices (SL) with embedded Ge dots. Spectroscopic ellipsometry (SE) measurement at room temperature was used to investigate optical and electronic properties of Si/Ge SL which were grown on silicon (Si) wafers having <111> crystallographic orientation. The results of the SE analysis between 200 nm and 1000 nm indicate that the SL system can effectively be described using interdiffusion/intermixing model by assuming a multicrystalline Si and Si1-xGex intermixing layers. The electronic transitions deduced from analysis reveal Si, Ge and alloying related critical energy points.