2021 Fiscal Year Final Research Report
Development of laser-irradiated acceptor activation technology of GaN super junction power devices for high-efficiency power systems
| Project/Area Number |
18K18866
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| Research Category |
Grant-in-Aid for Challenging Research (Exploratory)
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| Allocation Type | Multi-year Fund |
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| Review Section |
Medium-sized Section 21:Electrical and electronic engineering and related fields
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| Research Institution | Toyota Technological Institute |
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Principal Investigator |
Iwata Naotaka 豊田工業大学, 工学(系)研究科(研究院), 教授 (40708939)
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| Project Period (FY) |
2018-06-29 – 2022-03-31
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| Keywords | GaN / 有機金属気層成長法 / Mgアクセプタ / Siドナー / 活性化 / ArFエキシマレーザー / スーパー接合 / パワーデバイス |
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| Outline of Final Research Achievements |
We have developed a technique to activate acceptors by irradiating GaN co-doped with Mg and Si with an ArF excimer laser. Unlike heat treatment, laser irradiation can be activated only on the irradiated part. First, laser irradiation was performed using a Mg-doped GaN/Si-doped GaN structure wafer, and the activation of Mg was clarified by evaluating a vertical pn diode. Next, the relationship between irradiation intensity and acceptor activation was investigated in detail, and it was found that good activation can be obtained in a narrow intensity range of about 2 mJ/cm2, and at higher intensities activation was found to be suppressed and surface oxidation occurred. Based on these results, irradiation was performed using Mg/Si co-doped GaN, and photoluminescence and diode characteristics were investigated. As a result, increases in the emission intensity and concentration of the acceptor were obtained, and the activation of Mg was realized.
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| Free Research Field |
GaNを用いたパワーデバイスの研究開発
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| Academic Significance and Societal Importance of the Research Achievements |
有機金属気層成長法によるGaNは、ドープしたMgが水素と結合してアクセプタとして働かず、この活性化には熱処理が必要である。パルスレーザー照射は熱処理と異なり短時間の処理であるため、アクセプタの拡散を防ぐとともに照射する部分だけに活性化処理が施せる。この手法をMg/Si共ドープGaNに対して適用検討することで、照射部分にp型領域を形成し、照射しない部分のn型領域と縦方向に繰り返し並べたスーパー接合構造の実現を目論む。スーパー接合デバイスは、他のパワーデバイスとは異なり、オン抵抗と耐圧特性のトレードオフを大幅に改善するので、高効率な電力制御が可能となり、省エネルギー社会の実現に大きく寄与する。
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