CVD rhenium and PVD tantalum gate MOSFETs fabricated with a replacement technique

This letter reports the first replacement metal gate MOSFETs with chemical vapor deposition (CVD) Rhenium (Re), and physical vapor deposition (PVD) Tantalum (Ta) as the stacked gate electrode. Transistors with PVD Ta electrode are fabricated with a replacement and a nonself-aligned method for comparison. Our data show that CVD Re can be implemented as a gate electrode material for MOS transistors. The CVD Re process has the advantage of reducing the plasma and radiation damages to the gate oxide. A thick layer of PVD Ta covering a thin layer of CVD Re forms the stacked gate structure and makes the metal chemical-mechanical polishing feasible.