Interface properties of N2O-annealed SiC metal oxide semiconductor devices

Dry-oxidized and N2O-annealed n-type 6H-SiC metal-oxide-semiconductor capac itors are investigated at room temperature using a high-frequency C-V techn ique. Lower oxide-charge and interface-state densities are observed in case of dry-oxidized device. Oxide reliability of the capacitors is also invest igated under high-field stress. Compared to a dry-oxidized device, smaller change in interface-state density occurs for a nitrided device under high-f ield stress. On the other hand, positive flat-band shift of nitrided device is found to be larger after the stress, implying that the nitridation crea tes acceptor-type interface states and oxide traps in the device. In summar y, N2O nitridation improves the SiO2/n-type 6H-SiC interface and oxide hard ness against stress-induced damage. (C) 2001 Elsevier Science Ltd. All righ ts reserved.