MOS Interface Properties and MOSFET Performance on 4H-SiC{0001} and Non-Basal Faces Processed by N_2O Oxidation

摘要

4H-SiC(0001), (000-1), and (11-20) have been directly oxidized by N_2O at 1300℃, and the MOS interfaces have been characterized. The interface state density has been significantly reduced by N_2O oxidation on any face, compared to conventional wet O_2 oxidation at 1150℃. Planar n-channel MOSFETs fabricated on lightly-doped 4H-SiC(0001), (000-1) and (11-20) faces have shown an effective channel mobility of 26, 43, and 78 cm~2/Vs, respectively. The mobility decreased with increasing the doping concentration of p-body. SIMS analyses have revealed a clear pile-up of nitrogen atoms near the MOS interface. The thickness of interfacial SiC_xO_y layer can be decreased by utilizing N_2O oxidation. The crystal face dependence of interface structure is discussed.