2018 Fiscal Year Final Research Report

Correlation between deep-level defects and turn-on switching characteristics in AlGaN/GaN hetero-structures grown on Si substrates

Research Project

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Project/Area Number	16K06276
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Research Field	Electronic materials/Electric materials
Research Institution	Chubu University
Principal Investigator	NAKANO Yoshitaka 中部大学, 工学部, 教授 (60394722)
Research Collaborator	IROKAWA Yoshihiro SUMIYA Masatomo NIIBE Masato KAWAKAMI Retsuo
Project Period (FY)	2016-04-01 – 2019-03-31
Keywords	AlGaN/GaNヘテロ構造 / Si基板 / 3C-SiC層 / ターンオン・スイッチング特性 / 電流コラプス / 炭素 / 欠陥準位 / 熱的安定性
Outline of Final Research Achievements	AlGaN/GaN/GaN:C hetero-structures grown on Si substrates are one of the next generation of RF high power devices from a viewpoint of low production costs. At present, however, these GaN-based devices encounter undesirable bulk-related current collapse issues, where actual device performances at high frequencies can be easily limited by carbon-related deep-level defects in high resistive GaN:C layers. In this study, we have systematically investigated a detailed correlation between deep-level defects and turn-on switching characteristics in AlGaN/GaN/GaN:C hetero-structures fabricated on hetero-epitaxilly grown 3C-SiC/Si substrates. As the results, these hetero-strucures on 3C-SiC/Si substrates were found to expedite the turn-on switching characteristics in addition to the improvement of their thermal stability, compared to the conventional AlGaN/GaN/GaN:C hereo-structures on Si substrates.
Free Research Field	電気電子材料工学
Academic Significance and Societal Importance of the Research Achievements	Si基板上に結晶成長したAlGaN/GaNヘテロ構造は低コスト化・大面積化に適した次世代の高周波パワーデバイス用基板として期待されているが、高周波動作時にスイッチング特性が不安定となってしまう。本研究では、Si基板とAlGaN/GaNヘテロ構造の間に格子整合性の高い3C-SiC層を挿入することで、ターンオン時のスイッチング特性を大きく改善できることやこれらの熱的安定性が優れていることを見出した。これにより、SiC/Si基板上に形成したAlGaN/GaNヘテロ構造はバルク起因の電流コラプスを抑制でき、高周波パワーデバイスの開発は大きく加速されることが期待される。