A novel microwave plasma reactor for high rate deposition of a-Si : H films is described with a special attention paid on decreasing plasma maintenance power. The reactor is a coaxial-line type composed of stainless inner conductor and mesh outer conductor covering a quartz tube. Secondary electron emission and ECR effects decrease drastically the plasma maintenance power. Furthermore simple quantitative analysis of infrared absorption spectra of the a-Si : H films is presented also. This is basically the deconvolution of the spectra to two Gaussian functions, using least sqare method, but it contains analytic solutions, in part, to decrease CPU time
