Atmospheric pressure metal organic chemical vapor deposition of thin germanium films

Abstract

The deposition of thin germanium films by atmospheric pressure metal organic chemical vapor deposition at temperatures below 400 °C on substrates such as silicon wafers, float glass, and polyimide (Kapton®) using the diorganogermanes GeH2Cp4M2 and GeH2Cp*2 as molecular precursors is described. The deposition rates and thus the layer thicknesses can be varied by temperature and time to give layers with a thickness in the nanometer range. The homogeneity and roughness of the deposited films were analyzed by means of atomic force microscopy measurements showing the formation of smooth and uniform surfaces with roughnesses of the films in the range of (1 ± 0.15) nm to (4.5 ± 1.5) nm. Films with thicknesses between 50 and 750 nm were deposited and analyzed by Raman spectroscopy, vis–NIR spectroscopy, electron microscopy, energy dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). The as-deposited films are composed of amorphous germanium containing approximately 10% of carbon. Using Kapton® as a substrate highly flexible films were obtained.