Fabrication of group IV semiconductor alloys on Si substrate applying Al paste with screen-printing

Abstract

We investigated the influence of Sn and Ge ratio in Al paste to fabricate Si-based alloy semiconductor on large-area Si substrate using a conventional screen-printing process and high-temperature treatment steps. From the X-ray diffraction patterns, crystalline SiSn peaks with applying Al-Sn paste have been detected and Sn content in the SiSn layer was estimated around 0.35%, close to the level of solid solubility of Sn in Si. In addition, the Sn depth profile showed similar behavior with Al, which confirms the concept of a liquid epitaxial growth using Al. On the other hand, the SiGe peaks with applying Al–Sn–Ge paste were clearly observed and their main peaks were shifted to a higher angle linearly with decreasing the Ge ratio in the paste. It was suggested that Sn was segregated easily to the surface if in coexistence with Ge due to its lower solubility in SiGe systems.