Thermal desorption spectrometry study of Si1−xGex:H amorphous alloys

A thermal desorption spectrometry study of hydrogen from silicon germanium alloys is presented. Amorphous Si1−xGex:H (0 ≤ x ≤ 1) thin films were prepared by ion beam assisted evaporation on a substrate maintained at 120°C. Infrared spectrometry experiments showed that these alloys essentially contain silicon and germanium dihydride sites. Effusion experiments allowed us to deduce the Gibbs free energy of hydrogen desorption from the SiH and GeH sites as a function of the germanium content.