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The degration of the photoelectrical properties of a‐Si: H films grown by PECVD at different deposition conditions (reactor geometry, deposition rate) is investigated by irradiation of the samples with 20 keV electrons or light (AM 1). The dark‐ and photoconductivity as well as CPM are used to monitor the change of the sample properties during degradation and annealing. Using a multiple magnetic field assisted PECVD in coaxial geometry it is possible to increase the deposition rate at reduced degradation level. Significant differences between light and electron degradation cannot be obtained. It is found that with decreasing hydrogen content the stability of the photoelectrical properties can be improved. The measured CPM spectra are evaluated with respect to the localized gap DOS in dependence on the degradation level. The applied deconvolution procedure reveals a fixed position of the created defects (D−‐level) and in spite of the increasing slope of the Urbach tail E0 a constant slope of the valence‐band tail ET.