Oxidation, MOS Capacitors, and MOSFETs

Abstract

One of the most important advantages of SiC as a wide-energy-gap material is the high quality of the interface with its native oxide (Si02). It is this feature that is critical for the development of the most used semiconductor device the metal-oxide-semiconductor field-effect transistor (MOSFET). This chapter presents the current understanding of the interface and near-interface defects in thermally oxidized SiC. Particular emphasis is placed on the characterization techniques, given that nonequilibrium conditions, which appear owing to wide energy gap of SiC, lead to qualitatively different results from the case where these widely used techniques are applied to Si structures. A special section is devoted to nitridation of SiC-Si02 interfaces as the most promising technique for achieving the device-quality interfaces required for commercial applications. Finally, the performance of some of the power MOSFETs fabricated on SiC is presented. 9.1 Introduction Good bulk properties are sufficient for many useful applications of semiconductor materials. However, the dominant applications are critically dependent on both the bulk and the surface properties. It is the high density of surface defects that limits the application of many semiconductor materials with excellent bulk properties to niche applications. There are two semiconductor materials-silicon and silicon carbide-that can have surface defects passivated to levels that are significantly lower than the achievable surface density of current carriers. The passivation utilizes silicon dioxide, the native oxide of both silicon and silicon carbide. The successful passivation of the silicon surface, developed during the 1960s, means that current carriers (electrons and holes) can move over the semiconductor surface. This effect enables the operation of the metal-oxide-semiconductor field-effect transistor (MOSFET)-an electronic switch that is suitable for the integration of complex electronic systems. Consequently, very large-scale integration Z. C. Feng (ed.), SiC Power Materials