Microstructural characterization of rf sputtered polycrystalline silicon germanium films

Polycrystalline silicon germanium (Si1-xGex) films deposited by the rf sputtering technique were characterized using a combination of transmission electron microscopy (TEM), atomic force microscopy (AFM), x-ray diffraction (XRD), and Raman spectroscopy techniques. The TEM results showed small grains (10-20 nm) with microtwins, and AFM showed islands of 100-200 nm in the films. The XRD results show that our films consist of Si1-xGex alloy with no cluster of Ge or a Ge-rich material embedded in a Si matrix. The smaller grains in our films could be a result of an abundance of nucleating sites or impurities in the films. Raman spectroscopy results indicate that our films were strain free. (C) 2002 American Institute of Physics.