Effect of nitric oxide annealing on the interface trap densities near the band edges in the 4H polytype of silicon carbide

Results of capacitance-voltage measurements are reported for metal-oxide-se miconductor capacitors fabricated using the 4H polytype of silicon carbide doped with either nitrogen (n) or aluminum (p). Annealing in nitric oxide a fter a standard oxidation/reoxidation process results in a slight increase in the defect state density in the lower portion of the band gap for p-SiC and a significant decrease in the density of states in the upper half of th e gap for n-SiC. Theoretical calculations provide an explanation for these results in terms of N passivating C and C clusters at the oxide-semiconduct or interface. (C) 2000 American Institute of Physics. [S0003-6951(00)02113- 6].