Observation of reduced poly-gate depletion effect for poly-Si0.8Ge0.2-gated NMOS devices

Poly-Si0.8Ge0.2 and poly-Si gate n-channel metal oxide semiconductor capaci tors with very thin gate oxides were fabricated. Poly-gate depletion effect s (PDE) in these devices were analyzed. Lower sheet resistance, higher dopa nt activation rate, higher active dopant concentration near the poly/SiO2 i nterface, and, therefore, improved PDE were found in phosphorus-implanted p oly-Si0.8Ge0.2 gate as compared to poly-Si gate devices. As a result, poly- Si0.8Ge0.2 gate devices provide more inversion charge and therefore potenti ally provide higher current drive in metal oxide semiconductor transistors. (C) 1998 The Electrochemical Society, Inc. S1099-0062(98)02-034-3.