a-Si:H　films　were　grown　by　hot　filament　assisted　microwave　electron　synchrotron　resonance　chemical　vapor　deposition.　We　found　that　hot　filament　assistance　increases　the　deposition　rate　and　considerably　improves　the　film　stability;　and　that　the　deposition　rate　increase　with　the　increase　of　the　filament　temperature　and　the　pressure.　In　light-induced　degradation,　infrared　absorption　spectra　were　analyzed　with　baseline　fitting　and　Gaussian　data　fitting.　The　results　show　that　while　hydrogen　content　remains　unchanged,　the　relative　contents　of　Si-H　and　Si-H2　bonding　modes　changes.