Adhesion and bonding of polar and nonpolar SiC and AlN surfaces: Tight-binding band theory

Abstract

The atom superposition and electron delocalization tight-binding band theory has been used to characterize the interfacial binding between \ensuremath{\alpha}- and \ensuremath{\beta}-SiC and AlN. Binding is analyzed in terms of covalent and charge-transfer energy components with use of idealized unreconstructed surfaces. Adhesion energies are calculated to be strongest for Si/N and C/Al contacts between the nonpolar (101\ifmmode\bar\else\textasciimacron\fi{}0) and (112\ifmmode\bar\else\textasciimacron\fi{}0) surfaces. In the C/N and Si/Al orientations these interfaces show a charge rearrangement with C losing charge to Si and adhesion is very weak. For the interfaces between polar surfaces the C/N case has bond order 0 and no adhesion is predicted while the other possibilities have bond orders of (1/2 and adhesion energies in the order Si/N/AlC/Al. .AE