Research on Pd film deposition rate calculation and simulation based on TiZrV/Pd film coating experiment

TL;DR

This paper investigates the deposition rate of Pd films on TiZrV coatings in vacuum chambers, combining experimental SEM analysis with simulation based on Sigmund's theory to improve understanding of film coating processes.

Contribution

It introduces a method to estimate Pd film deposition rates using both experimental SEM data and theoretical simulation, enhancing coating process control.

Findings

Deposition rates vary with magnetic field, gas flow, current, voltage, and pressure.

Simulation results align with experimental data, validating the model.

Pd coating improves NEG film lifespan and H2 pumping efficiency.

Abstract

The vacuum chamber of accelerator storage ring need clean ultra-high vacuum environment. TiZrV getter film which was deposited on interior wall of vacuum chamber, can realize distributed pumping, effectively improve the vacuum degree and reduce the longitudinal gradient. But accumulation of pollutants such as N2, O2, will decrease the adsorption ability of non-evaporable getter (NEG), which leads to the reduction of NEG lifetime. Therefore, NEG thin film coated with a layer of Pd which has high diffusion rate and absorption ability for H2, can extend the service life of NEG, and improve the pumping rate of H2 at the same time. With argon as discharge gas, magnetron sputtering method was adopted to prepare TiZrV-Pd film in long straight pipe. According to the experimental results of the scanning electron microscope (SEM), deposition rates of TiZrV-Pd films were analyzed under different deposition parameters, the magnetic field strength, the gas flow rate, discharge current, discharge voltage and working pressure. Moreover, comparing the simulation results based on Sigmund's theory and experimental results, it was shown that the deposition rate C can be estimated by the depth sputtered, D for Pd film coatings in this experiment device.