Homoepitaxy on porous silicon

Abstract

Homoepitaxy on porous Si aims at producing monocrystalline thin silicon-on-insulator wafers or monocrystalline thin Si solar cells. There are two methods of preparation of the porous Si layer for homoepitaxy: on the one hand, the porous Si is reorganized at elevated temperatures to close the surface as a seed layer for epitaxy, and on the other hand, the reorganization of the porous Si is avoided to keep the open pore structure. For homoepitaxy on the porous Si layers, most research has been reported on the usage of atmospheric pressure chemical vapor deposition (APCVD). The quality of epitaxially grown Si layers, using different deposition techniques and various types of porous silicon, was assessed by etch pit density, minority carrier lifetime, Hall mobility, microscopy, and device performance. It can be concluded that APCVD is in combination with a closed porous Si surface layer as a seed layer, the most promising approach to produce high-quality epitaxial layers.