Spatial distribution of plasma parameters by a dual thermal-electrostatic probe in RF and DC magnetron sputtering discharges during deposition of aluminum doped zinc oxide thin films

Abstract

Aluminum doped zinc oxide thin films deposited by magnetron plasma sputtering are essential for various optoelectronic applications. So far, the oxygen negative ions and the atomic oxygen are regarded as responsible for the poor spatial uniformity of thin film resistivity. While various methods are available for thin film characterization, understanding the growth mechanism requires spatial-resolved measurements of plasma parameters. This work uses a dual thermal-electrostatic probe that is able to reveal the spatial distribution of plasma density, electron temperature and plasma potential. The results exhibit a parabolic profile for plasma density and flat profiles for electron temperature and plasma potential, with no correlation with the strong distribution of thin film resistivity that mirrors the erosion track on the target surface.