Deposition of silicon films from SiCl4 glow discharges: A kinetic model of the surface process

The deposition of amorphous silicon films from plasma-chemical reduction of silicon tetrachloride has been studied using optical emission spectroscopy, mass spectrometry, and laser interferometry as diagnostic techniques. The experimental results have been examined using a kinetic model of the surface processes. In the model, silicon tetrachloride (SiCI4 ) and silicon dichloride (SiCI2), chemisorbed on the growing surface, interact with hydrogen atoms to give free bond silicon species ( - SiClx ), which are reactive intermediates for the silicon-to-silicon bond formation on the surface. The temperature dependence of the deposition rate in the kinetic region has been also investigated. It has been established that the apparent activation energy for the silicon plasma deposition depends on the electronic character of the material (i.e., undoped, n, and p doped). As the surface becomes boron or phosphorus doped, the value of the apparent activation energy changes with respect to the undoped surface, as a result of the different chemisorption heat on the different surfaces.