Peculiarities of film growth in glow discharge with runaway electrons

We have studied the properties of films deposited in gas discharge with a beam of runaway electrons and observed for the first time an anomalous behavior of the intensity of a probing light beam reflected from a film on substrate upon switching off of the discharge. The observed phenomenon is interpreted in the framework of a two-layer model of the film growth on a substrate, according to which an optically homogeneous surface layer of unknown nature appears on the film during growth in discharge and fully decomposes when the discharge is switched off.