| 研究課題/領域番号 |
22K20438
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| 研究機関 | 豊田工業大学 |
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研究代表者 |
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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| 研究期間 (年度) |
2022-08-31 – 2024-03-31
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| キーワード | GaN / Laser activation / excimer laser |
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| 研究実績の概要 |
Main goal of the study is to realize Gallium nitride superjunction (GaN SJ) power device with p-GaN layer activated using an ArF laser. This will be an original proof of concept for this fabrication method. GaN SJ device is a candidate for next generation power devices. However, fabrication of SJ structure is very difficult, due to the alternating p- and n- layers needed. Although this can be achieved by selective ion implantation, a more elegant approach is to use selective excimer laser annealing, which can define the p-region (p-GaN) by laser irradiation. Research implementation plan includes three phases. Phase 1 includes optimization of the Mg-activation using ArF laser. Phase 2 includes feedback of optimized laser parameters to further tune the next batch of GaN wafer properties, and purchase the designed photomask for SJ device fabrication. And phase 3 includes the used of the optimized wafer and laser parameters to demonstrate actual SJ power device and characterization. Few months after we received Kakenhi Startup, initial results of ArF laser annealing of pGaN is presented during the JSAP spring conference 2023. The effectiveness of ArF laser annealing in the activation of Mg-doped GaN using cloverleaf mesa structure is investigated. Using hall measurement, laser irradiated pGaN showed that the resistivity increases as laser power is increased, implying that the laser power may have damage the surface. ArF laser annealing method using cloverleaf mesa structure is first successfully demonstrated. Further investigation needed to confirm pGaN activation.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
3: やや遅れている
理由
TThe preparation and alignment of the optical setup and UV camera for laser activation are done. Moreover, the fabrication of pGaN device using cloverleaf mesa structure has been established. This cloverleaf mesa structure will be used in the next fabrication of pGaN device for laser annealing optimization. Also, our laboratory has never used Indium (In) contact before, so after doing several deposition trials, now we can do In metal deposition via resistive evaporation. Also, we have shown initial data on the laser activation of pGaN with cloverleaf structure via ArF laser annealing during the JSAP spring 2023. However, the pGaN devices have high resistance contact, which causes problem during Hall measurement because Hall voltage signal is low. Thus, low pGaN contact resistance is needed. Currently, InAu metal is investigated as low resistance pGaN contact (ie thickness and contact annealing temperature). This needs to be addressed first before we can continue the optimization of laser activation.
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| 今後の研究の推進方策 |
In the near future, we want to optimize the InAu metal contact for better measurement of the resistivity and Hall voltages of the pGaN wafers. Whereas, in the future, we expect to finish the Phase 1 of the project, which is the optimization of the ArF laser pGaN activation using the current wafers. Then we will buy new batch of GaN wafers. Next is the purchase and design of the photomask for the GaN SJ device (Phase 2) and lastly, the fabrication of the GaN SJ device with pGaN activated using laser annealing (Phase 3).
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| 次年度使用額が生じた理由 |
We will buy new batch of GaN wafers before the year ends. The cost of the new GaN wafers are expensive, which will use most of my Kakenhi budget. It is important to properly evaluate the wafers that we have now, and then use the data to decide the new batch wafer configuration. Only then, we can buy the new batch of GaN wafers. Thus, the buying of new GaN wafers takes time.
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