No abstract

Nitric oxide (NO) post-oxidation annealing (POA) is an effective method for lowering the carbon component at an oxide/4H-SiC interface. However, this method has a drawback of additional oxidation by oxygen source from the NO gas. Atomic-layer-deposited (ALD) oxides subjected to ammonia (NH 3) annealing were employed to realize nitridation without oxidation process. Because NH 3annealed oxides have a drawback of high leakage current, deposition of dielectrics on ALD SiO 2 with subsequent NH 3 annealing were performed to reduce leakage current and to prevent oxidation, respectively. The employments of this process reduced interface trap density and surface roughness effectively while maintaining low leakage current.

In situ H 2 etching and homoepitaxial growth of 4H-SiC have been carried out on 4 • off-axis Si-face and C-face substrates by low-pressure chemical vapor deposition. We systematically analyzed H 2 etching characteristics and epitaxial growth of 4H-SiC substrates on two different polarities using an organosilicon source material, bistrimethylsilylmethane (C 7 H 20 Si 2 ). The effects of the growth conditions, such as growth temperature and source flow rate on the surface morphology, crystallinity, polytype conversion, defect generation, and structural imperfection of the epilayers on different polar surfaces, were investigated. High-quality epitaxial layers were successfully grown at low temperature range of 1320-1440 • C on the Si-face and 1500 • C on the C-face. A low source flow rate of 5-10 sccm was also preferred to grow defect-free epilayers.