InN growth and annealing investigations using in-situ spectroscopic ellipsometry

Abstract The thermal stability of InN in various ambients was investigated using in-situ spectroscopic ellipsometry. Improvement of the structural quality was found for annealing in nitrogen atmosphere in a narrow temperature window between 520 and 550 °C. Annealing in both, ammonia and hydrogen ambient generally led to a deterioration of the layers, leaving indium droplets on the surface. In contrast to GaN, InN surfaces cannot be stabilised by ammonia. Layer stability was strongly decreased in hydrogen, even at temperatures as low as 400 °C. For InN layer growth using ammonia and trimethylindium, the occurrence of a twist texture was found to define a lower limit of the growth temperature range. An upper limit is given by a competitive etching, depending on precursor supply.