Abstract
Coherent anti-Stokes Raman spectroscopy (CARS) is used to measure concentration profiles of molecules, time-dependent concentration changes, and temperature profiles in radio-frequency discharges of silane and some other gases, which are used to produce hydrogenated amorphous silicon and its related materials for electronic and opto-electronic applications. The results are discussed in terms of gas diffusion, dissociation and chemical reactions, as well as gas-phase thermal relaxation, thus giving an insight into the gas-phase kinetics involved in the material synthetic processes, which are important as the means for future process design and control. The advantages and limitations of CARS technique as a diagnostic tool for plasma deposition of materials are summarized, and the future scope of process diagnostics is discussed.
