Fabrication and characterization of BaSi2 epitaxial films over 1 μm in thickness on Si(111)

We attempted to fabricate a-axis-oriented BaSi2 epitaxial films up to 2180 nm in thickness. First, we investigated the influence of growth temperature and growth rate on the crystalline quality of approximately 400-nm-thick BaSi2 layers, and then optimized the above two growth conditions based on X-ray diffraction measurements. We next grew BaSi2 films with various layer thicknesses at 580 degrees C in the range between 100 and 2180 nm, and characterized their properties. The a-axis-oriented BaSi2 thick epitaxial films had three epitaxial variants rotating 120 degrees with each other around the surface normal. The microwave photoconductive decay measurements for the 1640-nm-thick BaSi2 epitaxial film showed that the minority-carrier lifetime was approximately 8 mu s at room temperature. These achievements open up the possibilities of thin-film solar cell applications of BaSi2. (C) 2014 The Japan Society of Applied Physics