Piezoelectric effects in GaN-based HEMTs and related devices and a new method

2017 Fiscal Year Final Research Report

• Project/Area Number: 26289095
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Electronic materials/Electric materials
• Research Institution: Toyota Technological Institute
• Principal Investigator: Sakaki Hiroyuki 豊田工業大学, 工学(系)研究科(研究院), 学長 (90013226)
• Co-Investigator(Kenkyū-buntansha): 大森 雅登 豊田工業大学, 工学(系)研究科(研究院), 嘱託研究員 (70454444) ; Vitushinsk Pavel 豊田工業大学, 工学(系)研究科(研究院), 研究補助者 (30545330) ; 秋山 芳広 豊田工業大学, 工学(系)研究科(研究院), 研究補助者 (60469773)
• Project Period (FY): 2014-04-01 – 2018-03-31
• Keywords: GaN / HEMT / ピエゾ効果 / 表面準位 / 界面準位 / 電界効果トランジスタ

Outline of Final Research Achievements

The change of the channel resistance in an AlGaN/GaN HEMT, induced by the bending of the sample is investigated. It is shown that this piezo-resistance results mainly from the change in the polarization charges which are generated at the surface and the interface regions of the sample by the piezoelectric effect in the wurtzite materials. As the polarization charge on the surface is partly compensated by the charges induced in surface states or a metal electrode, the surface state density can be evaluated by studying the piezo-resistance of two samples with and without the metal.
For comparison, the piezo-resistance of AlGaAs/GaAs HEMTs is studied to show that the resistance change in this system is due to the deformation-induced breakdown of crystal symmetry of the sample. It is found that this change of resistance results not only from the change in the electron concentration but also from the change of electron mobilities.

Free Research Field

半導体電子工学