Atomic Arrangement at the AlN/Si(110) Interface

GaN has been grown on Si(110) substrates by metalorganic vapor phase epitaxy using a low-temperature AlN nucleation layer. The atomic arrangement at the AlN/substrate interface has been investigated by high-resolution transmission electron microscopy. Lattice images of the AlN/Si interface taken along the <1120> AlN ∥<110> Si and <1100> AlN ∥<001> Si projections show an abrupt crystalline interface. A highly coherent epitaxial relationship between (1100) AlN and (001) Si planes is observed. The atomic bonding configuration at the AlN/Si interface is analyzed taking into consideration the chemical coordination, lattice mismatch, and net charge balance. A structure model of the bonding at the interface is presented.