Real Time Spectroscopic Ellipsometry Investigation of Homoepitaxial GaN Grown by Plasma Assisted Molecular Beam Epitaxy

The growth of GaN by plasma assisted molecular beam epitaxy on GaN template substrates (GaN on sapphire) is investigated with in-situ multi-channel spectroscopic ellipsometry. Growth is performed under various Ga/N flux ratios at growth temperatures in the range 710-780 degrees C. The thermal roughening of the GaN template caused by decomposition of the surface is investigated through the termporal variation of the GaN pseudodielectric function over the temperature range of 650 T to 850 T. The structural, morphological, and optical properties are also discussed.