Generation and pressure measurement of extremely high vacuum (XHV) using a TiN coated chamber

Abstract

A TiN coated chamber system has been developed to reduce outgassing from the walls of the vacuum chamber. The outgassing rate of the XHV chamber measured by the throughput method was 1 × 10−13 Pa m s−1. The outgassing rate measured by the pressure rise method using an extractor gauge (EXG) and a spinning rotor gauge was 3 × 10−10 Pa m s−1 and 2 × 10−13 Pa m s−1, respectively. The outgassing rate measured by the pressure rise method using the EXG is not correct because of outgassing from the gauge itself. The ultimate pressure measured by the EXG and an AxTran gauge was 3 × 10−10 Pa and 5 × 10−11 Pa, respectively. Pressure measurement using the EXG was limited to about 3 × 10−10 Pa because of factors such as x-ray effects, effect of electron stimulated desorbed ions and outgassing from the gauge itself. The results of outgassing and ultimate pressure measurement indicate that the coating of TiN film on surfaces of the vacuum chamber is effective in reducing the outgassing rate from the walls of the chamber.