Interface Properties of Metal–Oxide–Semiconductor Structures on 4H-SiC0001 and (1120) Formed by N2O Oxidation

4H-SiC(0001), (0001), and (1120) have been directly oxidized by N 2 O at 1300°C, and metal–oxide–semiconductor (MOS) interfaces have been characterized. The interface state density has been significantly reduced by N 2 O oxidation on any face, compared to conventional wet O 2 oxidation at 1150°C. Planar n-channel metal–oxide–semiconductor field-effect transistors (MOSFETs) fabricated on 4H-SiC(0001), (0001) and (1120) faces have shown effective channel mobilities of 26, 43, and 78 cm 2 /Vs, respectively. Secondary ion mass spectrometry analyses have revealed a clear pileup of nitrogen atoms near the MOS interface. The thickness of the interfacial transition layer can be decreased by N 2 O oxidation. The crystal face dependence of the interface structure is discussed. A simple consideration of chemistry indicates that NO, generated from the decomposition of N 2 O, may be a more efficient oxidant of carbon than O 2 .