Investigation into the influence of buffer and nitrided layers on the initial stages of GaN growth on InSb 100/

Radio frequency plasma-assisted molecular beam epitaxy MBE.growth of GaN on InSb 100.has been investigated. This combination is interesting because a 458 rotation of a cubic epitaxial GaN layer could result in a nearly Alattice-matchedB system. The growth of low-temperature buffer layers and initial substrate nitridation at 2758C on the morphology of the subsequent growth at 4508C were considered. Nitridation produced a smooth, mixed InN and Sb–N layer, whilst annealing to 4508C resulted in the loss of the Sb nitride component and disruption of the InN, causing exposure of the underlying substrate and surface roughening. Similarly thin buffer layers ;8 A°.were found to crystallise and island at 4508C but allowed substrate damage. By contrast, thicker buffer layers ;80 A°.remained smooth and continuous and protected the substrate but did not crystallise. Subsequent growth morphologies reflected the surface quality of the underlying layers, however all layers were polycrystalline wurtzite GaN and no evidence was found for crystalline cubic GaN formation. q2000 Elsevier Science B.V. All rights reserved.