Investigation of charge build-up in NO nitrided gate oxide on 4H-SiC during Fowler-Nordheim injection and fabrication of 4H-SiC Lateral Double-Implanted MOSFETs

The charge build up in gate oxide and the field effective mobility of 4H-SiC Lateral Double Implanted Metal-Oxide-Semiconductor Field-Effect Transistors (DIMOSFETs) have been evaluated for its dependence on the Post-Oxidation Annealing (POA) time in a nitric oxide gas ambient. NO nitrided oxide for 3 hours significantly reduces the interface trap density near the conduction band and effective oxide charge density, resulting in a decrease of oxide trapped charge in gate oxide during Fowler-Nordheim injection as compared with that of NO POA for 1-2 hours. A high field effect mobility of 11.8 cm²/Vs was successfully achieved in Lateral DIMOSFETs with NO POA for 3 hours. The electrical properties of metal-oxide semiconductor devices fabricated using these oxides are discussed in terms of the oxide´s chemical composition.