Influence of post-deposition annealing on interfacial properties between GaN and ZrO2 grown by atomic layer deposition

Influence of post-deposition annealing on interfacial properties related to the formation/annihilation of interfacial GaOx layer of ZrO2 grown by atomic layer deposition (ALD) on GaN is studied. ZrO2 films were annealed in N-2 atmospheres in temperature range of 300 degrees C to 700 degrees C and analyzed by X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy. It has been found that Ga-O bond to Ga-N bond area ratio decreases in the samples annealed at temperatures lower than 500 degrees C, which could be attributed to the thinning of GaOx layer associated with low surface defect states due to "clean up" effect of ALD-ZrO2 on GaN. However, further increase in annealing temperature results in deterioration of interface quality, which is evidenced by increase in Ga-O bond to Ga-N bond area ratio and the reduction of Ga-N binding energy. (C) 2014 AIP Publishing LLC.