SIMS investigation of the influence of Ge pre‐deposition on the interface quality between SiC and Si

Abstract

AbstractSiC/Si(111) heterostructures formed by using an alternative method for stress relaxation were investigated by SIMS and AES. The applied stress reduction method is based on a theoretical approach, which predicts an improvement of the SiC layer quality if Group IV elements are incorporated into the interface between SiC and Si. Germanium was chosen to test this approach. The incorporation of Ge into the heterointerface was carried out by depositing different amounts of Ge prior to the SiC growth process and varying the Ge deposition temperature. SIMS investigations revealed that Ge remains near the SiC/Si interface independently of the pre‐deposited amount of Ge. In the case of two monolayers (ML) Ge coverage (with respect to the silicon surface) a surface segregation was observed. This indicates a limited transport of Ge to the SiC surface through the growing SiC layer due to grain boundary diffusion. At Ge coverages between 0.5 ML and 2 ML a sharper interface between the SiC and Si was observed. In this case the tail of the carbon distribution remains within the region occupied by the Ge distribution. The incorporation of Ge at the interface suppresses the out‐diffusion of Si from the substrate to the surface of the growing SiC layer and, therefore, impedes the formation of voids at the SiC/Si interface. Copyright © 2004 John Wiley & Sons, Ltd.