Effect of process variations and ambient temperature on electron mobility at the SiO2/4H-SiC interface

We report the effect of processing variables on the inversion layer electron mobility of (0001)-oriented 4H-SiC n-channel MOSFETs. The process variables investigated include: i) implant anneal temperature and ambient; ii) oxidation procedure; iii) postoxidation annealing in nitric oxide (NO); iv) type of gate material, and v) high-temperature ohmic contact anneal. Electron mobility is significantly increased by a postoxidation anneal in NO, but other process variations investigated have only minor effects on the channel mobility. We also report the temperature dependence of electron mobility for NO and non-NO annealed n-channel MOSFETs.