Ellipsometry studies of Si/Ge superlattices with embedded Ge dots

TL;DR

This study uses spectroscopic ellipsometry to analyze the optical and electronic properties of Si/Ge superlattices with embedded Ge dots, revealing interdiffusion effects and critical energy points related to Si, Ge, and their alloys.

Contribution

It introduces a spectroscopic ellipsometry analysis method for Si/Ge superlattices with embedded Ge dots, highlighting interdiffusion effects and electronic transition insights.

Findings

Effective description of superlattices using interdiffusion/intermixing model

Identification of critical energy points related to Si, Ge, and alloys

Spectroscopic ellipsometry response analysis between 200 nm and 1000 nm

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.