"Current Status and Future Prospects of Gallium Oxide-based Optoelectronics"

Dr. Masataka Higashiwaki, Director, National Institute of Information and Communications Technology, Tokyo, Japan

August 11th (Monday), 2:00pm
Engineering Science Building (ESB), Room 2001

Gallium oxide (Ga2O3) has excellent material properties for power device applications represented by the extremely large breakdown field of 8 MV/cm due to its large band gap of 4.6~4.9 eV. Another important feature in industry is that large single-crystal β-Ga2O3 substrates can be fabricated from a melt-grown bulk. We recently succeeded in fabricating Ga2O3 metal-oxide-semiconductor field-effect transistors (MOSFETs) on single-crystal Ga2O3 (010) substrates by using newly developed technologies for making single-crystal substrates, growing conductivity-controlled epitaxial films, and fabricating devices. The MOSFETs exhibited excellent device characteristics including an off-state breakdown voltage of over 400 V, an extremely low leakage current (below the lower limitation of the measurement instrument), and a high on/off drain current ratio of more than 10 orders of magnitude. The devices also showed good performance at 250°C with no significant permanent degradation. These results indicate that Ga2O3 have comparable or even more potential than Si and typical widegap semiconductors SiC and GaN for power device applications. R&D works on InGaN LEDs on Ga2O3 substrates that a collaborative company Tamura Corporation is conducting are also introduced briefly at the end of this seminar.

About Dr. Masataka Higashiwaki:

photo of masataka higashiwaki Masataka Higashiwaki received the B.S., M.S., and Ph.D. degrees all in solid-state physics from Osaka University, Osaka, Japan, in 1994, 1996, and 1998, respectively. From 1998 to 2000, he continued his experimental work on molecular-beam epitaxy (MBE) growth of self-organized GaAs quantum wires at Osaka University as a post doctorial research fellow of the Japan Society for the Promotion of Science. In 2000, he joined the Communications Research Laboratory (CRL), Tokyo, Japan, as a Researcher, where he was engaged in research and development on MBE growth and device processing of group-III nitride-based transistors. From 2004 to 2007, he was a Senior Researcher of the National Institute of Information and Communications Technology (NICT), which was renamed from CRL in 2004. From 2007 to 2010, he took a temporary leave from NICT and joined the Department of Electrical and Computer Engineering, University of California, Santa Barbara as a Project Scientist. He returned to NICT in 2010 and is now a Director at Green ICT Device Advanced Development Center.

Dr. Higashiwaki was a recipient of several awards for his work on GaN and Ga2O3-based transistors, including the 2013 Frontier Technology Award of Fuji Sankei Business i, the 2009 The Research Encouragement Award of Marubun Research Promotion Foundation, the 2007 International Symposium on Compound Semiconductors (ISCS) Young Scientist Award, and the 2006 Japan Society of Applied Physics (JSAP) Outstanding Achievement Award for the Best Original Paper. He has authored and co-authored about 100 papers in technical journals and international conferences, including about 30 invited talks.

Hosted by: Professor Umesh Mishra