Fabrication of 4H-SiC DIMOSFETs by High-Temperature (>1400°C) Rapid Thermal Oxidation and Nitridation Using Cold-Wall Oxidation Furnace
A passivation annealing in nitric oxide (NO) ambient significantly reduces the interfacial defects of the SiO2/4H-SiC interface and improves the inversion MOS channel mobility. Effects of the nitridation in NO ambient become more pronounced at high temperatures in general. However, the maximum process temperature in a standard hot-wall oxidation furnace is restricted around 1200oC due to the softening point of quartz. Meanwhile, by use of a cold-wall oxidation furnace, high temperature and short time thermal processes become possible. In this study, we have developed an extremely high temperature (>1400oC) rapid thermal processing for the gate oxidation in the 4H-SiC DIMOSFET fabrication process. The peak MOS channel mobility of lateral MOSFETs on the DIMOSFET chip shows as high as 19cm2/Vs. The specific on-resistance of the device was 12.5mcm2 and the blocking voltage was 950V with gate shorted to the source.
Robert P. Devaty, David J. Larkin and Stephen E. Saddow
R. Kosugi et al., "Fabrication of 4H-SiC DIMOSFETs by High-Temperature (>1400°C) Rapid Thermal Oxidation and Nitridation Using Cold-Wall Oxidation Furnace", Materials Science Forum, Vols. 527-529, pp. 1309-1312, 2006