Effect of Surface Potential on Piezoresistivity for Semi-conductive Nanowires

2020 Fiscal Year Final Research Report

• Project/Area Number: 18H01335
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 18010:Mechanics of materials and materials-related
• Research Institution: Kobe University
• Principal Investigator: Isono Yoshitada 神戸大学, 工学研究科, 教授 (20257819)
• Co-Investigator(Kenkyū-buntansha): 菅野 公二 神戸大学, 工学研究科, 准教授 (20372568)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: MEMS / SiC / Nanowire / Field effect transistor / 表面電位

Outline of Final Research Achievements

In order to clarify the effect of surface potential on the piezoresistive effect of SiC nanowires (NWs), FET-type bending test devices including single SiCNW wrapped by SiO2 or Al2O3 dielectric materials were fabricated, and the gauge factor of SiCNWs was evaluated by varying the gate voltage under bending straining. The FET characteristics in the unstrained state showed n-type electron transport characteristics when the SiO2 shell with a positive fixed oxide charge was used as the dielectric, and p-type characteristics when the Al2O3 shell with a negative fixed oxide charge was used. In the resistance change rate of SiCNW under bending straining, the SiO2-coated NW showed a negative gauge factor such as n-type semiconductors, while Al2O3-coated NW had a positive gauge factor. Furthermore, the gauge factors changed significantly with the increase or decrease of the gate voltage.

Free Research Field

MEMS、実験ナノメカニクス

Academic Significance and Societal Importance of the Research Achievements

本研究で得られた、半導体ナノ細線のピエゾ抵抗効果に及ぼす表面電位と弾性ひずみの影響に関する知見は、超小型機械量センサの実現に資するものである。低不純物濃度をもつ半導体ナノ細線おいて、そこにわずかに含まれる不純物を考慮してシェルを効果的設計・形成することで巨大なピエゾ抵抗効果を発現しうること、またそれを外部電界により制御しうることが示された。本研究で評価を行ったSiCはワイドギャップ半導体の一つであることから、その高温下での優れた材料特性と本研究で得られた知見を活用することで、過酷環境下で高信頼性をもつ超小型機械量センサへの応用が期待される。