Analysis of Si/SiGe Intermixing Layer Thickness by Inductively Coupled Plasma – Mass Spectrometry

A new method for characterizing the intermixing layer between epitaxially deposited Si and SiGe based on the atomic scale wet etch combined with Inductively Coupled Plasma – Mass Spectrometry (ICP-MS). The thermally induced Ge and Si interdiffusion is considered as one of the root causes for the poor process control and undesired cavity profile after etch, which, in turn, may significantly impact the device performance. The developed ICP-MS method allows us to analyze the thickness of the Si/SiGe intermixing layer and the Ge concentration profile, which can help to improve the upstream processes.