Epitaxial growth of Si:C/Si/SiGe into cavity formed by selective etching of SiGe

Epitaxial growth of Si:C, Si or SiGe in the cavity formed by selective vapor phase etching of sacrificial SiGe layer by HCl using a RPCVD system was investigated. The sacrificial SiGe layer was etched with very high selectivity. Epitaxial Si was deposited into the selectively etched cavity by non-selective and selective deposition processes. Weak strain contrast was observed by TEM at the interface where the growthfronts from top and bottom of the cavity were meeting each other. No or weak strain contrast was observed in the Si cap layer at middle to shallow part of the cavity.By non-selective SiGe growth, the SiGe layer was deposited on the Si cap layer only. The Si cap layer on the cavity seems to be bended and pressed down in the early stage of non-selective SiGe growth. On the other hand, in the case of selective SiGe growth, the cavity was filled. Strain contrast was observed by TEM in the Si cap layer on selectively grown SiGe. Bending of Si cap layer after selective SiGe growth was increased with increasing Ge concentration, indicating that tensile strain was generated by SiGe growth in the cavity.