Fabrication and characterization of sub-quarter-micron MOSFETs with a copper gate electrode

Sub-0.25-μm P- and N-MOSFETs with a chemical vapor deposited copper gate electrode were fabricated using a novel nitride cast method wherein a silicon nitride gate is used as a stand-in gate which is then replaced by Cu with a PVD TiN barrier metal after source/drain formation. The maximum processing temperature after copper deposition is 400/spl deg/C. Excellent device performance was obtained on both P- and N-MOSFET. No signs of copper diffusion were observed after device fabrication and after bias-temperature stress tests at 200/spl deg/C.