Electrical properties, structural properties, and deep trap spectra of thin α-Ga2O3 films grown by halide vapor phase epitaxy on basal plane sapphire substrates
Dae-Woo Jeon,
Hoki Son,
Jonghee Hwang,
A. Y. Polyakov,
N. B. Smirnov,
I. V. Shchemerov,
A. V. Chernykh,
A. I. Kochkova,
S. J. Pearton,
In-Hwan Lee
Affiliations
Dae-Woo Jeon
Korea Institute of Ceramic Engineering and Technology, 15-5, Chungmugong-dong, Jinju, Gyeongsangnam-do 52851, South Korea
Hoki Son
Korea Institute of Ceramic Engineering and Technology, 15-5, Chungmugong-dong, Jinju, Gyeongsangnam-do 52851, South Korea
Jonghee Hwang
Korea Institute of Ceramic Engineering and Technology, 15-5, Chungmugong-dong, Jinju, Gyeongsangnam-do 52851, South Korea
A. Y. Polyakov
National University of Science and Technology MISiS, 4 Leninskiy Ave., Moscow 119049, Russia
N. B. Smirnov
National University of Science and Technology MISiS, 4 Leninskiy Ave., Moscow 119049, Russia
I. V. Shchemerov
National University of Science and Technology MISiS, 4 Leninskiy Ave., Moscow 119049, Russia
A. V. Chernykh
National University of Science and Technology MISiS, 4 Leninskiy Ave., Moscow 119049, Russia
A. I. Kochkova
National University of Science and Technology MISiS, 4 Leninskiy Ave., Moscow 119049, Russia
S. J. Pearton
Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611, USA
In-Hwan Lee
Department of Materials Science and Engineering, Korea University, Seoul 02841, South Korea
Undoped epitaxial films of α-Ga2O3 were grown on basal plane sapphire substrates by halide vapor phase epitaxy (HVPE) in three different modes: standard HVPE, HVPE with constant flow of Ga and pulsed supply of O2 (O2-control growth regime), and with constant flow of O2 and pulsed delivery of Ga (Ga-control growth fashion). The best crystalline quality as judged by x-ray symmetric and asymmetric reflection half-widths and by atomic force microscopy morphology profiling was obtained with the O2-control deposition, and these results appear to be the best so far reported for α-Ga2O3 films. All grown α-Ga2O3 epilayers were high-resistivity n-type, with the Fermi level pinned near Ec − 1 eV deep traps. Photoinduced current transient spectra also showed the existence in standard HVPE samples and samples grown under the O2-control pulsed growth conditions of deep hole traps with levels near Ev + 1.4 eV whose density was suppressed in the Ga-control pulsed HVPE samples. The levels of the dominant deep traps in these α-Ga2O3 samples are close to the position of dominant electron and hole traps in well documented β-Ga2O3 crystals and films.
