Characteristics of MOS Capacitors with NO and POCl3 Annealed Gate Oxides on (0001), (11-20) and (000-1) 4H-SiC

MOS capacitors have been fabricated on (0001), (11-20) and (000-1) oriented 4H-SiC under different post-oxidation anneal (POA) conditions. 100 MHz conductance measurement shows the generation of very fast donor-type interface traps after NO anneal for both Si-face (0001) and a-face (11-20), but not on C-face (000-1). Fast traps were not observed in POCl3 annealed samples for any orientation. Smallest Dit (at 0.2 eV below conduction band edge) was obtained on Si-face using POCl3 anneal (1.4x1011 cm-2 eV-1), on a-face using NO anneal (2.5x1011 cm-2 eV-1) and on C-face using POCl3 anneal (4.5x1012 cm-2 eV-1).