2023 Fiscal Year Research-status Report
Development of GaN superjunction devices with pGaN ArF laser activation for high power application
| Project/Area Number |
22K20438
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| Research Institution | Toyota Technological Institute |
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Principal Investigator |
VILLAMIN MARIAEMMA 豊田工業大学, 工学(系)研究科(研究院), ポストドクトラル研究員 (00960874)
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| Project Period (FY) |
2022-08-31 – 2025-03-31
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| Keywords | GaN / Laser activation / excimer laser / ArF activation annealing / Mg doped GaN |
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| Outline of Annual Research Achievements |
Main goal is to realize GaN SJ device with p-GaN region selectively activated via ArF laser. This will be an original proof of concept for SJ structure fabrication that is difficult to make due to alternating p-&n- layers needed. ArF laser activation of Mg-doped GaN device was investigated. We have achieved laser activation resistivity comparable to thermally activated Mg-doped GaN, which suggest feasibility of laser activation. Our results reveal some insights on the fundamental activation mechanism of laser annealing, that is probable thermal mechanism is responsible for acceptor laser activation. Also, it is still a challenged to achieve good ohmic contact for p-GaN device.So, we also studied Indium as low temperature annealed contact& achieved low contact resistance with In/Au metal
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| Current Status of Research Progress |
Current Status of Research Progress
3: Progress in research has been slightly delayed.
Reason
We have presented laser activation annealing of an Mg-doped GaN four-point probe small mesa device using ArF excimer laser in SPIE photonics west 2024 (international conference). And just submitted a paper in a journal.
We have also presented some results to domestic conferences and international conference within japan. We also bought the co-doped GaN wafers last year. However, the Gallium export restrictions from Chinese government result to longer delivery lead time. Currently, I am still waiting for the delivery of the co-doped wafer and continuously talking with Enkris about the possible delivery date. This delay on wafer delivery is the only reason for the slightly delayed status.
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| Strategy for Future Research Activity |
While waiting for the co-doped wafer delivery, we are continuously improving the laser activation annealing setup. That is, different program of the programmable laser scanning stage will be investigated in preparation for the fabrication of GaN SJ device. Moreover, if the co-doped wafers will be received, we plan to immediately do laser activation on a small area device and then, scan a bigger area using laser scanning. And if possible, do fabrication of the device.
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| Causes of Carryover |
We bought the third batch of co-doped GaN wafers last year. However, the Gallium export restrictions from Chinese government result to longer delivery lead time. Before the restriction, it took only 1 month for the delivery of the ordered wafers, but now it is indefinite. Currently, I am still waiting for the export license approval, thus wafers are not yet delivered.
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