Effects of hillocks and post-growth annealing on electrical properties in GaN grown by metalorganic chemical vapor deposition

We have studied the effects of growth conditions of GaN buffer layer on the properties of GaN epilayer which was grown by metalorganic chemical vapor deposition technique. As nucleus size was increased by growth conditions of the GaN buffer layer, hillocks dominated surface morphology. The hillocks were detrimental to the electrical properties of GaN epilayer because they enhance the incorporation of electrically active impurities. From post-growth annealing, it was proposed that dislocations and/or carbon are the electron Hall mobility limiting compensators.