FT-IR Analysis of the Photolytic Laser-Induced Chemical Vapor Deposition of Germanium Films

Germanium and doped-germanium polycrystalline films were formed with the use of photolytic CO 2 laser-induced chemical vapor deposition. The compounds which yielded germanium in large quantities were germane, ethylgermane, and diethylgermane. Triethylgermane produces germanium in trace quantities. Gas-phase reactions were monitored with the use of Fourier transform infrared spectroscopy, also used for identification of end products. Scanning electron microscopy was used for analysis of the films. The products identified on irradiation of germane were germanium and hydrogen, with conversion rates of 86%. On irradiation of diethylgermane and ethylgermane, ethylene, germane, germanium, and hydrogen were produced. Germanium films doped with cadmium and aluminum were produced successfully by the irradiation of germane mixtures containing dimethylcadmium or trimethylaluminum, respectively.