Metal silicide-templated growth of quality Si films for Schottky-diodes

Abstract

Quality Si films were grown on a metal silicide template and fabricated for a Schottky-diode. The thin metal was firstly deposited and reacted to the supplying Si and then formed the silicide layer, which is a template to grow quality Si film above it due to the lattice affinity to Si. Various types of metal (Co, Ni, and mixture of Co and Ni) were used as catalyst species. The morphological changes of Si grain sizes were systematically investigated. Two steps of Si supply condition were applied and revealed the formation of metal silicide phases and Si film growth. During the Si supply, Co was stable to form CoSi 2 and grew a crystalline Si (c-Si) film above it. However Ni firstly formed Ni rich silicide phases at low Si supply due to the fast Ni diffusion in Si. By increasing the Si supply, Ni diffusion has been staggered and formed NiSi 2 layer to grow a c-Si film above it. It has been also revealed that the NiSi 2 migration produced a c-Si film behind. Mixing of Co with Ni showed a stable silicide phase without a serious metal migration and improved the Si crystallinity providing an enhanced Schottky-diode performance. The investigation of silicide formation and quality Si film growth is presented. Transmission electron microscope analysis proves the volume growth of c-Si film above a metal disilicide of NiSi 2 or CoSi 2.