The electronic stability of a‐Si:H films deposited by different methods and a wide range of preparation parameters has been investigated by keV‐electron irradiation. Employing an electron dose of about 70 J/cm2a metastable defect density near its saturation level was created. The defect density of the initial and the irradiated state has been determined by CPM and PDS. It was found that the saturation level of the creation of metastable defects &Dgr;Nsatis independent on the previous (stable) defect density Nowithin the experimental inaccuracy. Meanwhile an evident increase of &Dgr;Nsatwith the hydrogen content CH‐fraction bonded at inner surfaces, and the optical gap was observed. Obviously, there exists a dependence of &Dgr;Nsaton the preparation temperature. The saturation behaviour of the films does not always correlate with that of pin solar cells prepared with the same i‐material.