Characteristics of Silicon Silicon-Dioxide Structures Formed by DC Reactive Sputtering

Abstract

The C-V characteristics of silicon silicon-dioxide structures fabricated using DC reactive sputtering method were investigated. The fast interface states were able to be eliminated by subjecting the sample to high temperature treatment in inert gas flow and subsequent Al-treatment. The surface state charge Q _{s s} was of the order of 10¹⁰ q·cm^-2 in the sample treated in nitric acid prior to oxide deposition. The substitution of a hydrofillic pretreatment for the nitric pretreatment resulted in a negative Q _{s s} of approximately -5×10¹¹ q cm^-2. This small Q _{s s} was stable under bias-temperature stressing at 300°C even without additional processing, and, on the other hand, the negative Q _{s s} could be stabilized with comparable ease by forming the usual phosphate glass layer on the oxide. This stable negative Q _{s s} is of interest from the viewpoint of practical application such as making normally off n-channel MOS transistors.