A NEW TYPE OF TRANSDUCER FOR PARTIAL-PRESSURE CONTROL

A new transducer for controlling the partial pressure of sputtering gases is described. Utilizing the electron impact emission spectroscopy (EIES) principle, an instrument capable of operating in a total pressure environment of 100×10-3 Torr or more with minimum detectable partial pressures to 10-7 Torr is also described. These capabilities seem ideal for controlling reactive deposition processes utilizing N2, O2 or hydrocarbons. Because of the high operating pressure capabilities, this transducer does not require the complication of high vacuum pressure reduction and thus eliminates a major source of unscheduled maintenance. The operating principles of EIES and the sensitivities that were determined for the various gases tested are described in this paper. This technique has high stability over extended periods of time and sufficient sensitivity to control processes of practical interest. This technique also has utility for monitoring common residual gases such as H2O and CO2, in an analyzer mode, as a precursor to starting the reactive process. The applications of the control equipment in producing titanium nitride films are discussed.