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

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 times 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 times 10-10 Pa m s-1 and 2 times 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 times 10-10 Pa and 5 times 10-11 Pa, respectively. Pressure measurement using the EXG was limited to about 3 times 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. [PUBLICATION ABSTRACT]