Cross sectional CL study of the growth and annihilation of pit type defects in HVPE grown (0001) thick GaN

The growth and annihilation mechanism of pit type defects in HVPE grown thick GaN films was studied using a cross sectional cathodoluminescence (CL) technique. Two kinds of pit type defects were distinguished by their morphology: the hexagonal V-pit surrounded by {10−11} facets and the U-pit with {10−11} facets having a blunt bottom. It was found that the V-pit originated from different growth rates between (0001) plane and {10−11} facet, and was filled and annihilated by {10−12} facets’ growth, namely U-pit generation. The formation of U-pit may play an important role in annihilation of pit type defects.

► Growth and annihilation mechanism of pits was studied by a cross sectional CL.
► Two kinds of pits were separated: V-pit by {10−11} facets, and U-pit of blunt bottom.
► V-pit originated from different growth rates between (0001) and {10−11} facets.
► V-pit was filled and annihilated by {1012} facets growth (U-pit generation).
► Formation of U-pit may play an important role in annihilation of the pits.