High mobility NMOSFET structure with high-/spl kappa/ dielectric

Abstract

High-/spl kappa/ NMOSFET structures designed for enhancement mode operation have been fabricated with mobilities exceeding 6000 cm/sup 2//Vs. The NMOSFET structures which have been grown by molecular beam epitaxy on 3-in semi-insulating GaAs substrate comprise a 10 nm strained InGaAs channel layer and a high-/spl kappa/ dielectric layer (/spl kappa//spl cong/20). Electron mobilities of >6000 and 3822 cm/sup 2//Vs have been measured for sheet carrier concentrations n/sub s/ of 2-3/spl times/10/sup 12/ and /spl cong/5.85/spl times/10/sup 12/ cm/sup -2/, respectively. Sheet resistivities as low as 280 /spl Omega//sq. have been obtained.