Recent progress on low-temperature epitaxial growth of nitride semiconductors

Indium nitride films were grown on (111)GaAs substrates by reactive magnetron sputtering using an indium target. It was found that the crystal quality of InN films depends strongly on the substrate temperature and sputtering gas pressure, and highly c-axis preferred wurtzite InN films can be obtained at growth temperature as low as 100 degreesC. The influence of the substrate pretreatment on crystallinity of indium nitride films was also investigated. It was shown that the crystalline quality of InN layers grown on GaAs can be improved by presputtering the substrate in nitrogen plasma prior to the growth. By Auger electron spectroscopy and atomic force microscopy analysis we revealed that GaN islands form on the surface of GaAs substrate due to the presputtering. The optimum presputtering time for growing InN single crystal was assessed to be the time at which GaN islands cover the substrate surface entirely.