Improved short channel device characteristics with stress relieved pre-oxide (SRPO) and a novel tantalum carbon alloy metal gate/HfO/sub 2/ stack

Threshold voltage instability is a critical problem for high-K dielectric implementation. This problem is much more serious for short channel devices due to process induced gate edge damage. A novel stress relieved pre-oxide (SRPO) followed by ALD of HfO/sub 2/ reduces the local charge density near the gate edge and short channel threshold voltage instability. Excellent cross wafer CETinv uniformity is achieved for the SRPO process. A new tantalum carbon alloy metal gate achieves a lower Vtsat than TaSiN gated devices due to a lower work function. Compared to HfO/sub 2//TaSiN devices using standard RCA pre-clean, HfO/sub 2//tantalum carbon alloy metal gate stack using the novel SRPO demonstrates a 3/spl times/ smaller Vt shift for short channel devices and a 16% Ion/Ioff improvement.