A detailed examination of the valence band discontinuity (ΔEυ) formed at the (0001), (0001), and (1100) interfaces between 2H-AlN and 6H-SiC has been conducted using x-ray and UV photoelectron spectroscopies. The ΔEυ was observed to range from 0.6-2.0 eV depending on 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 ΔEυ of 1.4-1.5 eV was observed for AlN grown on (3 × 3) (0001)Si6H-SiC on-axis substrates; a ΔEυ of 0.9-1.0 eV was observed for off-axis substrates with the same surface reconstruction. The values of ΔEυ for AlN grown on (√3 × √3)R30°(0001) 6H-SiC on-and-off-axis substrates were 1.1-1.2 eV. A larger valence band discontinuity of 1.9-2.0 eV was determined for 3C-SiC grown on (0001) 2H-AlN. Smaller values of ΔEυ of 0.6-0.7 and 0.8-0.9 eV were observed for AlN grown on on-axis (0001)C and (1100)6H-SiC substrates, respectively.
ASJC Scopus subject areas
- Physics and Astronomy(all)