Influence of the Nonuniform Thickness of a Dielectric Film along a Cathode Surface on Its Heating in a Glow Discharge

Journal of Surface Investigation: X-Ray, Synchrotron and Neutron Techniques. 2025. Vol. 19. No. 1. P. 66–72.

Bondarenko G., Fisher M. R., Kristya V. I.

A model of a cathode layer in a gas glow discharge is formulated taking into account the presence
of a dielectric film with varying thickness on the cathode across different areas of its surface, and in some
areas, the film may be absent. The model includes ion–electron emission from the cathode surface, thermalfield
electron emission from the cathode substrate into the film, and thermal electron emission from the areas
of the cathode without a film. Upon heating the cathode, the emission efficiency of the film, the effective
electron emission yield of the cathode, and the discharge current density decrease, as the electric-field intensity
within the film decreases. This decrease in field strength limits the current density required to sustain the
thermal-field electron emission from the cathode substrate into the film. Therefore, when a dielectric film
covers the entire working surface of a cathode, the glow discharge does not transition to an arc discharge for
a long time. However, if the film is absent on some areas of the cathode surface, thermal electron emission begins
from these areas after heating the cathode to a rather high temperature. The emitted electrons leave the cathode
surface, which increases the effective electron emission yield and discharge current density. This leads to more
intense heating of the cathode and accelerates the transition of the glow discharge into an arc discharge.

Keywords: glow discharge, тлеющий разряд, диэлектрическая пленка, dielectric film, поверхность катода, Cathode Surface