GOX 2022 Session KEY1: Keynote Address
Monday, August 8, 2022 8:30 AM in Room Jefferson 2-3
Monday Morning
Session Abstract Book
(244KB, Oct 9, 2022)
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| 8:45 AM |
KEY1-2 Keynote Lecture: Ga2O3 Device Technologies: Power Switching and High-Frequency Applications, and Beyond
Masataka Higashiwaki (Department of Physics and Electronics, Osaka Metropolitan University); Takafumi Kamimura, Sandeep Kumar, Zhenwei Wang (National Institute of Information and Communications Technology); Takahiro Kitada, Jianbo Liang, Naoteru Shigekawa (Department of Physics and Electronics, Osaka Metropolitan University); Hisashi Murakami, Yoshinao Kumagai (Department of Applied Chemistry, Tokyo University of Agriculture and Technology) Developments of Ga2O3 field-effect transistors (FETs) and diodes are being actively conducted all over the world. From the world-first demonstration of single-crystal Ga2O3 FETs in 2011 [1], we have been developing both vertical and lateral Ga2O3 devices. In this talk, our latest selected challenges on vertical Ga2O3 Schottky barrier diodes (SBDs), vertical Si/Ga2O3 heterostructures, and lateral short-gate Ga2O3 FETs will be discussed. Ga2O3 SBDs with a trench staircase field plate were fabricated [2]. We found that the staircase field plate on the deep trench filled with SiO2 can effectively alleviate electric field concentration in both the Ga2O3 drift layer and the SiO2. The Ga2O3 SBDs successfully demonstrated superior device characteristics including an on-resistance of 7.6 mΩcm2 and an off-state breakdown voltage of 1.66 kV. Next, our pioneering work on vertical n-Si/n-Ga2O3 heterostructures fabricated using surface-activated bonding will be presented [3]. Analyses of temperature-dependent current density–voltage characteristics of the heterostructures revealed that an energy barrier was formed at the Si/Ga2O3 heterojunction interface due to negatively charged interface states. The conduction band offset at the bonding interface was estimated to be 0.18 eV. We have also been developing lateral Ga2O3 FETs with a highly scaled gate for high-frequency and logic applications in harsh environments. Submicron-gate Ga2O3 FETs with a thin channel layer formed by Si-ion implantation doping achieved promising device performance typified by a maximum oscillation frequency of 27 GHz at a gate length of 200 nm [4]. These works were supported in part by the Ministry of Internal Affairs and Communications (MIC) research and development (JPMI00316) and JSPS KAKENHI Grant Number 19H02182, Japan. [1] M. Higashiwaki, K. Sasaki, A. Kuramata, T. Masui, and S. Yamakoshi, Appl. Phys. Lett. 100, 013504 (2012). [2] S. Kumar, H. Murakami, Y. Kumagai, and M. Higashiwaki, Appl. Phys. Express, in press. [3] Z. Wang, D. Takatsuki, J. Liang, T. Kitada, N. Shigekawa, and M. Higashiwaki,J. Appl. Phys. 131, 074501 (2022). [4] T. Kamimura, Y. Nakata, and M. Higashiwaki, Appl. Phys. Lett. 117, 253501 (2020). |