| 研究課題/領域番号 |
18K14139
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| 研究機関 | 島根大学 |
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研究代表者 |
Pham Hoang.Anh 島根大学, 学術研究院理工学系, 助教 (60750213)
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| 研究期間 (年度) |
2018-04-01 – 2021-03-31
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| キーワード | Thin film / Aluminum film / Gold film / Laser annealing / Selective growth / Single crystal |
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| 研究実績の概要 |
In the FY2019, we investigated the effect of reflectivity on the laser annealing process of the sputtered Al films. The Al thin films were deposited by sputtering with thickness varied from 15 nm to 100 nm. At the laser wavelength 405 nm, the reflectivity of the thermally deposited film (50 nm thick) was 66%, while the reflectivity of the sputter-deposited films was 80-96%, which increased with film thickness. Within this range of reflectivity, stable growth of single-grain crystal could not be maintained. We have tried Al-Si3N4 and Al-Si2O sandwich structure to control the reflectivity. The reflectivity of Al (20 nm) - Si4N3 (36 nm) can be reduced to 67%. However, single-grain crystal could not be obtained. It was probably that the energy was mainly absorbed by Si4N3 layer instead of Al.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
By changing the sputtering parameters, the Al film thickness and surface roughness can be controlled, but the reflectivity still remained high (>80%). Application of Al-Si3N4 sandwich structure reduced further the reflectivity, but the energy absorption by Al film was insufficient to maintain a stable melting pool for single-grain growth.
We also investigated the laser annealing process of Au thin films 40-60 nm thick. Au film was melted easily by laser annealing, but single grain growth could not be realized. The reason could be the high vapor pressure of Au at its melting point and poor wettability of Au on SiO2 substrate. At lower laser power, we observed solid stage grain growth in Au films, leading to surface smoothening, formation of strong (111) texture with large grain sizes.
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| 今後の研究の推進方策 |
Through this study, the effect of reflectivity, vapor pressure and wettability of the metal on the single-grain crystal growth by laser annealing has been understood. A new laser annealing system is being built with the ability to adjust the laser wavelength. By this way, the wavelength corresponding to the minimum reflectivity of Al films (about 810 nm) can be used to optimize the laser annealing process of sputter-deposited Al thin films.
In the FY2020, we are also going to investigate the effect of SiO2 cap layer on the laser annealing process of Au films. The application of SiO2 cap layer is to suppress evaporation of Au melt due to its high vapor pressure. By this way, the Au melting pool is expected to be stabilized for single-grain crystal growth.
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| 次年度使用額が生じた理由 |
Purchase of Au thin films was delayed due to personnel changes of the providing company. We are plane to order Au sputtering target to prepare the Au films by ourselves.
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