Surface conductivity change by oxidation of the homoepitaxially grown diamond (100) surface

Abstract

We have investigated the electrical conductivity change that occurs by oxidation of a homoepitaxially grown diamond (100) surface. For this purpose, atomically flat diamond (100) surfaces homoepitaxially grown by a microwave plasma-assisted chemical vapor deposition (MPCVD) were prepared. It is well-known that a CVD-grown diamond surface is a hydrogen-chemisorbed structure. Surface chemisorbed structures of diamond can be controlled by oxidation in air at temperatures from 25 °C up to 350 °C. The degree of oxygen-chemisorption on the diamond surfaces was analyzed by X-ray photoelectron spectroscopy (XPS). The electrical resistivity (or conductivity) of the diamond surfaces was measured at room temperature under nitrogen flow by using the van der Pauw four-probe system. The surface resistivity of diamond was drastically increased at 300-350 °C, a temperature range corresponding to the beginning point of surface oxidation of a diamond analyzed by the XPS. © 2007 IOP Publishing Ltd.