FUNDAMENTAL ELECTRICAL-PROPERTIES OF FLUORINATED AND N2O PLASMA-ANNEALED ULTRATHIN SILICON-OXIDES GROWN BY MICROWAVE PLASMA AFTERGLOW OXIDATION AT LOW-TEMPERATURES

A technique for growing ultrathin silicon oxides of superior quality a t low temperatures is indispensable for future submicron device applic ations. Fundamental characteristics such as the oxide breakdown fields , oxide charges, and interface-state densities of various ultrathin si licon oxides (less than or equal to 8 nm) grown by microwave plasma af terglow oxidation at low temperatures (400 and 600 degrees C) were inv estigated. Fluorination (HF soaking) and low-temperature N2O plasma an nealing were employed to improve the properties of the oxides. The bre akdown fields of the as-grown silicon oxides were enhanced and the int erface-state densities were reduced. The effect of N2O annealing time on the interface-state density was also investigated. A longer anneali ng time (>1 h) was required to reduce the interface-state density. The effective oxide charge density of 600 degrees C as-grown oxide was as low as 6x10(10) cm(-2). Additionally, the breakdown field of the thin silicon oxide grown at 600 degrees C with 15 min N2O plasma annealing was 12 MV/cm.