The mechanism by which electron — ion bombardment affects the growth of a silicon nitride film obtained by reactive sputtering in an apparatus based on a Penning discharge is investigated. The temperature and the degree of irradiation of the substrate are determined as functions of the distance from the substrate to the aperture in the anode. It is established that the presence or absence of bombardment leads to a difference in the formation of reactively sputtered silicon nitride films.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 11–15, December, 1976.The authors thank Yu. E. Kreindel' for his interest in the work and for useful discussions.