Presentation Information
[WBP1-14]Optimization of Eclipse Nd:YAG-Pulsed Laser Deposition method for YBCO Thin Films: Suppressing Droplets via Definitive Screening Design
*Eijiro Okumura1, Gen Ieda1, Sota Tarumi1, Tsuyoshi ogawa1, Noriyuki Taoka1, Yoshiyuki Seike1, Tatsuo Mori1, Yusuke Ichino1,5, Keiichi Horio2,5, Ataru Ichinose3,5, Tomoya Horide4,5, Kaname Matsumoto4,5, Yutaka Yoshida4,5 (1. Aichi Inst. of Technol. (Japan), 2. Kyushu Inst. of Technol. (Japan), 3. Cent. Res. Inst. of Elect. Power Ind. (Japan), 4. Nagoya Univ. (Japan), 5. JST-CREST (Japan))
Keywords:
YBCO thin films,Nd:YAG-PLD,eclipse,droplet,precipitate
Pulsed laser deposition (PLD) is a powerful technique for fabricating YBa2Cu3Oy (YBCO) superconducting thin films. However, in Nd:YAG PLD, droplet ejected from the target remains a major issue, contaminating surfaces and degrading superconducting properties. To address this, we investigated an eclipse PLD system, in which a shadow mask physically blocks droplets during film growth.
YBCO films were deposited on SrTiO3 (100) substrates at 950 °C under 53 Pa oxygen for one hour, with a substrate–target distance of 50 mm. Two mask parameters were varied: width (0, 5, 10 mm) and distance from the substrate (15, 25, 35 mm). A Definitive Screening Design (DSD) was employed to efficiently identify the influence of these factors. Droplet densities were quantified by scanning electron microscopy, and superconducting transition temperatures (Tc) were evaluated.
The results indicated that a mask width of 5–10 mm strongly suppressed large droplets on the film surface. The optimal condition was identified as a mask width of 5 mm placed 15 mm from the substrate. Under these settings, droplet density was minimized. Nevertheless, small precipitates with areas below ~1.5 µm2 remained, which were attributed to non-stoichiometric film composition and contributed to moderate reductions in Tc.
In summary, the eclipse PLD method with optimized mask geometry provides an effective route to suppress droplet contamination. Future work will apply DSD to parameters such as substrate temperature, oxygen pressure, and laser energy in order to further reduce precipitates and achieve improved film performance.
YBCO films were deposited on SrTiO3 (100) substrates at 950 °C under 53 Pa oxygen for one hour, with a substrate–target distance of 50 mm. Two mask parameters were varied: width (0, 5, 10 mm) and distance from the substrate (15, 25, 35 mm). A Definitive Screening Design (DSD) was employed to efficiently identify the influence of these factors. Droplet densities were quantified by scanning electron microscopy, and superconducting transition temperatures (Tc) were evaluated.
The results indicated that a mask width of 5–10 mm strongly suppressed large droplets on the film surface. The optimal condition was identified as a mask width of 5 mm placed 15 mm from the substrate. Under these settings, droplet density was minimized. Nevertheless, small precipitates with areas below ~1.5 µm2 remained, which were attributed to non-stoichiometric film composition and contributed to moderate reductions in Tc.
In summary, the eclipse PLD method with optimized mask geometry provides an effective route to suppress droplet contamination. Future work will apply DSD to parameters such as substrate temperature, oxygen pressure, and laser energy in order to further reduce precipitates and achieve improved film performance.