In situ infrared transmission spectroscopy of nucleation and growth of amorphous hydrogenated silicon

We present a series of IR transmission spectra with submonolayer resolution of the initial growth of amorphous hydrogenated silicon (a-Si:H) deposited by F-2 laser (157 nm) chemical vapor deposition. The film thickness was measured simultaneously using a quartz crystal microbalance with appropriate sensitivity. The presented technique allows the evolution of the H content and bonding configuration on a silicon substrate to be monitored during nucleation and growth. It provides a comparable or even higher sensitivity than that achieved by reflection absorption spectroscopy using metal surfaces or methods applying multilayer ''optical cavity'' structures to enhance the IR absorption. (C) 1996 American Institute of Physics.