Method and apparatus for deposition of metal nitrides

A physical vapor deposition system, comprising:

• chamber walls forming a chamber;
• a support to hold a workpiece in the chamber;
• a vacuum pump to evacuate the chamber;
• a gas source to deliver nitrogen gas and an inert gas to the chamber;
• an electrode supporting a niobium target;
• a power source to apply power to the electrode;
• and
• a controller configured to
• before a workpiece on which a metal nitride layer is to be deposited is placed in the chamber, cause the gas source to flow nitrogen gas and the inert gas at a first flow rate ratio of nitrogen gas to inert gas into the chamber and cause the power source to apply power sufficient to ignite a first plasma in the chamber to pre-condition the chamber while the nitrogen gas and the inert gas are flowing at the first flow rate ratio,
• after the workpiece is placed in the chamber, cause the gas source to flow nitrogen gas and the inert gas at a second flow rate ratio of nitrogen gas to inert gas into the chamber, wherein the second flow rate ratio is less than the first flow rate ratio and comprises less nitrogen gas than the first flow rate ratio, and
• cause the power source to apply power sufficient to ignite a second plasma in the chamber while the nitrogen gas and the inert gas are flowing into the chamber at the second flow rate ratio such that the critical temperature of a resulting metal nitride layer is increased as compared to the second flow rate ratio being greater than the first flow rate ratio and to deposit the resulting metal nitride layer having a critical temperature of at least 9.7 Kelvin on the workpiece by physical vapor deposition.