The Distribution and Erosion Characteristics of Plasma Particles in Magnetron Sputtering Under Different Excitation Voltage Sources

Abstract

Magnetron sputtering is widely used in thin film fabrication and surface modification of materials. During the sputtering process, the spatial species distribution significantly impacts the deposited film’s properties. However, there are still some difficulties in understanding the spatial species distribution, transport and energy control, resulting in uneven coating and low target utilization. In this article, we utilized a 2-D magnetron sputtering plasma model to further investigate the species distribution of the plasma under different excitation voltage sources and consequently obtain the Ar+ sputtering energy distribution. The erosion phenomenon was studied in the transport of ions in matter (TRIM) software, and the particle energy and angle obtained from the plasma simulation were used as input to study the incident distribution and sputtering yield. The results show significant differences in the distribution, density, and sputtering energy of plasma under dc, radio frequency (RF) (13.56 MHz) and high-power pulse (HPP) excitation voltage sources. Under dc, the electron distribution is more uniform than other excitation sources, covering 40%–50% of the target surface area. The initial sputtering energy distribution ranges from 0 to 400 eV with an erosion depth of 20Å, and the sputtering yield is approximately proportional to the voltage. The sputtering yield increases slower under RF when the voltage reaches 1000 V. Under RF, the electric field distribution is uniform at 800 V, but Ar+ is concentrated covering only 15% of the target surface. Under HPP, the electron and Ar+ densities reach $10^{{17}}$ – $10^{{18}}$ m ${}^{-{3}}$ , with the highest electron current density reaching $5\times 10^{{3}}$ A/m2. The sputtering depth is 30Å. This research has significant importance in optimizing the process parameters of magnetron sputtering and improving film performance. It provides strong support for the development and application of magnetron sputtering processes.