HVPE Growth and Characterization of Thick <i>κ</i>-Ga<sub>2</sub>O<sub>3</sub> layers on GaN/Sapphire Templates
С. И. Степанов, В. И. Николаев, A. Y. Polyakov, А. И. Печников, E. B. Yakimov, M. P. Scheglov, Ivan Shchemerov, A.A. Vasil'ev, А. I. Kochkova, A. V. Chernykh, A. V. Chikiryaka, P. N. Butenko, S. J. Pearton
Abstract
Ga 2 O 3 layers with thickness from 10 to 86 μ m were grown by halide vapor phase epitaxy (HVPE) on GaN(0001)/sapphire templates in a hot wall reactor at 570 °C, with the growth rate of about 3–4 μ m h −1 . The grown layers consisted of pure (001)-oriented κ -Ga 2 O 3 polymorph with no admixture of β -Ga 2 O 3 or α -Ga 2 O 3 phases. The narrowest (004) X-ray rocking curves were observed for 13–20 μ m thick κ -Ga 2 O 3 layers. A further increase in thickness results in deterioration of the crystal quality which is indicated by the broadening of rocking curves. Electrical measurements of the thick layers revealed that they were n-type, with the concentration of shallow donors gradually decreasing from ∼10 16 cm −3 to ∼10 15 cm −3 . Deep level transient spectroscopy (DLTS) measurements revealed the presence of deep traps with levels near E c −0.3 eV, E c −0.6 eV, E c −0.7 eV, E c −0.8 eV, E c −1 eV, with the E c −0.8 eV being predominant.