SiH 4 exposure of GaN surfaces: A useful tool for highlighting dislocations

Fast-turnaround, accurate methods for the assessment of threading dislocation densities in GaN are an essential research tool. Here, we present an in-situ surface treatment for use in MOVPE (metal-organic vapour phase epitaxy) growth, in which GaN is exposed to a SiH 4 flux at 860 °C in the presence of NH 3 . Subsequent characterisation by atomic force microscopy shows that the treatment is effective in increasing edge and mixed/screw dislocation pit sizes on both n - and p -type material, and on partially coalesced GaN layers.