Formation of a miscibility gap in laser-crystallized poly-SiGe thin films

Abstract

AbstractLaser-crystallized polycrystalline silicon-germanium (poly-SiGe) thin films on glass substrates were characterized with energy dispersive X-ray and Raman spectroscopy. In the course of the crystallization strong lateral segregation occurs for laser-crystallized poly-Si1-xGex with 0.33 < x < 0.7, causing the local Ge content to differ by as much as 40 % from the average value. The segregation manifests itself in the appearance of well-resolved peaks in the Raman phonon modes. This mode splitting in the Raman spectra is interpreted as the formation of well defined alloy phases with a miscibility gap in between.