Study on the thermal stability of InN by in-situ laser reflectance system

Abstract

The thermal stability of InN in the growth environment in metalorganic chemical vapor deposition was systematically investigated in situ by laser reflectance system and ex situ by morphology characterization, X-ray diffraction and X-ray photoelectron spectroscopy. It was found that InN can withstand isothermal annealing at temperature as high as 600 °C in NH 3 ambient. While in N 2 atmosphere, it will decompose quickly to form In-droplets at least at the temperature around 500 °C, and the activation energy of InN decomposition was estimated to be 2.1±0.1 eV. Thermal stability of InN when annealing in NH 3 ambient during temperature altering would be very sensitive to ramping rate and NH 3 flow rate, and InN would sustain annealing process at small ramping rate and sufficient supply of reactive nitrogen radicals. Whereas In-droplets formation was found to be the most frequently encountered phenomenon concerning InN decomposition, annealing window for conditions free of In-droplets was worked out and possible reasons related are discussed. In addition, InN will decompose in a uniform way in the annealing window, and the decomposition rate was found to be in the range of 50 and 100 nm/h. Hall measurement shows that annealing treatment in such window will improve the electrical properties of InN.