(135e) Sic Surface Preparation by Hydrogen Cleaning for High-Temperature, High-Power Device Integration

A hydrogen-etch based process has been developed that effectively converts rough, oxide contaminated Silicon Carbide (SiC) surfaces into smooth, clean, hydrogen-terminated surfaces with atomic steps. In order to create novel, robust, high-power, high-frequency devices based on wide bandgap SiC, a well controlled, clean, and atomically smooth substrate surface is necessary. Silicon Carbide wafers received from commercial vendors contain scratches, micropipes, oxides, and other containments that can impede the growth of thin films. Although there are demonstrated methods for preparing the SiC surface in the literature, chemical composition studies of these surfaces are lacking, and can be important for understanding thin film nucleation and growth.

A hydrogen furnace, that has been designed and custom built, has demonstrated the ability to produce atomic level steps, as seen by Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). In addition, Auger Electron Spectroscopy (AES) and X-ray Photoelectron Spectroscopy (XPS) scans show negligible oxygen while displaying characteristics of a clean SiC surface. By varying H2:Ar flow ratios and SiC surface temperature, operating windows that avoid hydrogen over-etching and still remove the surface contaminants have been determined. The final hydrogen-terminated surface has been demonstrated to be stable for 24 hours in laboratory air.