Novel damage-free direct metal gate process using atomic layer deposition

Abstract

We report the impact of atomic layer deposition (ALD)-TiN on the novel characteristics of the W/TiN/SiO/sub 2//p-Si MOS system. A damage-free direct metal gate was attained using ALD-TiN as manifested by the negligible hysteresis and low interface trap density (D/sub it/) of /spl sim/5/spl times/10/sup 10/ eV/sup -1/cm/sup -2/ near the Si midgap. Gate leakage current level gated with ALD-TiN is remarkably lower than that with physical vapor deposition (PVD)-TiN or poly-Si gate at a similar capacitance equivalent thickness (CET). In addition, ALD-TiN demonstrated highly robust gate oxide reliability with negligible CET variation against high thermal budget, paving the way for the direct metal gate process.