Research on physical properties of electrode interface on wide-gap semiconductor by a new sress measurement by Raman spectroscopy

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K05296
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 30010:Crystal engineering-related
• Research Institution: Chukyo University
• Principal Investigator: Jun Suda 中京大学, 工学部, 教授 (20369903)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 顕微ラマン分光 / ワイドギャップ半導体 / 熱応力 / 局所的電子物性 / 電子移動度 / 電子密度 / 比抵抗 / 金属積層薄膜電極

Outline of Final Research Achievements

In this study, we analyzed thermal stress on several kinds of n-type widegap semiconductors in contact with an electrode up to 200℃ using micro-Raman spectroscopy and compared with those obtained by FEM analysis. The values of thermal stress were proportional to the temperature We also calculated　electron density, electron mobility, and resistivity in all of cases. In GaN,the dislocation density increasing with thermal stress with stress-temperature coefficient clearly. The density of lattice defects near the interface at 200℃ may be elevated by high thermal stress in plane near the interface.The increase in the density of lattice defects may be the reason why the resistivity values near the interface tended to increase significantly with increasing temperature in comparison with those far from the interface. This would lead to a clear increase in the switching power loss of widegap semiconductors with electrode film at high temperatures in power electronics applications.

Free Research Field

結晶工学

Academic Significance and Societal Importance of the Research Achievements

高温ラマンイメージング実験により数種類の電極付ワイドギャップ半導体の電極界面の熱応力を求めると同時にLOPCモードの電子物性解析を行い，GaNでは電極近傍における比抵抗の特性を非破壊測定できることに成功し，高温電子物性と熱応力の関係の一端を明らかにした．本研究方法を応用すると．高温動作時の大電力パワーエレクトロニクスにおいて熱応力によるワイドギャップ半導体のスイッチング損失の増加特性を予測できる．また，電極付サンプルにおいて電極近傍のラマン線幅は電極遠方に対して広がっており，振動数シフトと線幅の相関から熱応力を求めることが可能であると考えられる．