The surface topography of GaN grown on Si (1 1 1) substrate before and after wet chemical etching

Surface topography of GaN layer grown on Si (1 1 1) using metalorganic chemical vapor deposition before and after etching were investigated by plan-view transmission electron microscopy and scanning electron microscopy. Different shape of etch pits appeared on GaN with different thickness, and typical pits which reflected the dislocation interaction always occurred at the junction of sub-grains. The mechanism was discussed.