Silicon Wafer Orientation Dependence of Metal Oxide Semiconductor Device Reliability

The reliability of very thin gate oxides is studied using Si(100) and Si(111) wafers. When Si(111) wafer is oxidized to form thick oxide such as field oxide, the Si–SiO2 interface microroughness increases. The increased microroughness degrades the dielectric breakdown characteristics. Moreover, the oxide films on Si(111) are inferior to those on Si(100) in reliability even when the Si–SiO2 interface microroughness is of the same level. Oxide quality is determined by silicon wafer orientation.