A detailed examination of the valence band discontinuity (ΔEv) formed at the (00•1), (00•¯1), and (1¯1•0) interfaces between 2H–AlN and 6H–SiC was conducted using X-ray and UV photo-electron spectroscopy. The ΔEv was observed to range from 0.6 to 2.0eV, depending upon the growth direction (i.e., AlN on SiC vs SiC on AlN), as well as the crystallographic orientation, cut of the SiC substrate (i.e., on versus off axis), and SiC surface reconstruction and stoichiometry. A ΔEv of 1.4 to 1.5eV was observed for AlN grown on (3 x 3)-(00•1)Si6H–SiC on-axis substrates; a ΔEv of 0.9 to 1.0eV was observed for off-axis substrates with the same surface reconstruction. The values of ΔEv for AlN grown on (√3 x √3)R30°(00•1) 6H–SiC on-and-off-axis substrates were 1.1 to 1.2eV. A larger valence band discontinuity of 1.9 to 2.0eV was determined for 3C–SiC grown on (00•1) 2H–AlN. Smaller values of ΔEv of 0.6 to 0.7 and 0.8 to 0.9eV were observed for AlN grown on on-axis (00•¯1)C and (1¯1•0)6H–SiC substrates, respectively.

Valence Band Discontinuity, Surface Reconstruction, and Chemistry of (00•1), (00•¯1), and (1¯1•0) 2H–AlN/6H–SiC Interfaces. S.W.King, R.F.Davis, C.Ronning, M.C.Benjamin, R.J.Nemanich: Journal of Applied Physics, 1999, 86[8], 71-3