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阳极层离子源可输出高密度离子束流，广泛用于等离子体清洗和辅助沉积，但大束流下内部易发生放电击穿，且大量离子轰击内外阴极导致明显刻蚀， 易造成样品污染。本文提出阳极环绕磁屏蔽罩和内外阴极溅射屏蔽板的设计方案， 并仿真研究了其对离子源电磁场和等离子体放电输运的影响。发现阳极环绕磁屏蔽罩可切断离子源内部阴阳极间的磁场回路，消除打火条件。内外阴极溅射屏蔽板选择溅射产额低且绝缘性能好的氧化铝， 即可阻挡离子溅射， 又能屏蔽阴极外表面电场，使等离子体放电向阳极压缩，在抑制阴极刻蚀行为的同时提升离子输出效率。当距离阴极外表面 9 mm 时， 溅射屏蔽板的作用效果最优，不仅能获得稳定放电和高效输出，还可大幅削弱阴极刻蚀行为并减少污染。实验结果显示，改进离子源无内部打火，输出高效且清洁， 相同电流下离子输出效率较原离子源实际提高 36%，玻璃基片在经过 1 h 清洗后，表面成分几乎不变， 来自阴极溅射的 Fe 元素含量仅为 0.03%，比原离子源低 2 个数量级， 含量约为原离子源的 0.6%， 实验结果验证了理论分析。Large beam-anode layer ion source can produce high-density ions, and has been widely used in plasma cleaning and assisted deposition. However, when increasing the ion-beams, arcing always occurs inside the ion source and serious etching will take place on the cathode which results in sample pollution especially in long-time cleaning. This work proposes two designed structures, called magnetic shields surrounding the anode and sputtering shields on the top of the inner and outer cathodes, respectively. The influence of the designed structure on the electromagnetic field and the plasma properties of the ion source are studied by a self-established simulation techniques based on the particle-in-cell/Monte Carlo collision method and test particle Monte Carlo method. The results show that the magnetic shields surrounding the anode cut off the magnetic induction line between the cathode and anode, which eliminates the arcing condition in the ion source. The sputtering shields for the cathodes use alumina ceramics because of the extremely low sputtering yield and high insulation performance. Therefore, the sputtering shields can not only resist the ion sputtering, but also shield the electric field on the outer surface of the cathode. As a result, the plasma discharge region is compressed towards the anode and away from the cathode simultaneously, which provides a stronger electric field force directed to the output region for Ar+ ions, also resulting in a suppressed cathode etching behavior but an improved Ar+ ion output efficiency. The optimized calculation shows that the best distance from the sputtering shields to the cathode surface is 9 mm. The discharge experiments reveal that the modified ion source can eliminate the inside arcing and provide a clean and strong ion beam with a high efficiency. At the same discharge current, the output efficiency of the modified ion source is 36% higher than that of the original ion source. When used in the plasma cleaning, the glass substrate remains transparent and keeps the original element composition ratio. The detected Fe content, comes from the cathode sputtering, is only 0.03% after the plasma cleaning for 1 h, which is 2 orders of magnitude smaller than that cleaned by the original ion source. The Fe content of the modified ion source is about 0.6% of the original ion source, which is in good agreement with the result of simulation optimization.
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Keywords:
- Large beam-anode layer ion source /
- Cathode etching /
- Electromagnetic shielding /
- Output properties
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[1] Harper J M E, Cuomo J J, Kaufman H R 1982 J. Vac. Sci. Technol. A 21 737
[2] Zhao J, Tang D L, Cheng C M, Geng S F 2009 Nucl. Fusion. Plasma. Phys. 29 5 (in Chinese) [赵杰, 唐德礼, 程昌明, 耿少飞 2009 核聚变与等离子体物理 29 5]
[3] Lackner J M, Waldhauser W, Schwarz M, Mahoney L, Major B, 2008 Vacuum. 83 302
[4] Lee S, Kim D G 2015 J. Funct. Anal. 24 162
[5] Dudnikov V 2012 Rev. Sci. Instrum. 83 02A713
[6] Chen L, Cui S H, Tang W, Zhou L, Li T J, Liu L L, An X K, Wu Z C, Ma Z Y, Lin H, Tian X B, Ricky K Y Fu, Paul K Chu, Wu Z Z 2020 Plasma Sources Sci. Technol.29 025016
[7] Guo X Y, Cao Y S, Ma J P 2021 China Patent (in Chinese) [郭杏元, 曹永盛, 马金鹏 2021 中国专利]
[8] Wang L S, Tang D L, Cheng C M 2006 Nucl. Fusion. Plasma. Phys. 26 54 (in Chinese) [汪礼胜, 唐德礼, 程昌明 2006 核聚变与等离子体物理 26 54]
[9] Zheng J, Zhou H, Zhao D C 2019 China Patent (in Chinese) [郑军, 周晖, 赵栋才 2019 中国专利]
[10] Wang M, Chen G 2020 China Patent (in Chinese) [王鸣, 陈刚 2020 中国专利]
[11] Brenning N, Gudmundsson J T, Raadu M A, Petty T J, Minea T, Lundin D 2017 Plasma Sources Sci. Technol. 26 125003
[12] Jiang Y, Tang H, Ren J, Li M, Cao J 2018 J. Phys. D: Appl. Phys 51 035201
[13] Yu D R, Zhang F K, Liu H, Li H, Yan G J, Liu J Y 2008 Phys. Plasmas. 15 104501
[14] Birdsall C K 1991 IEEE Trans Plasma Sci. 19 65
[15] Li T J, Cui S H, Liu L L, Li X Y, Wu Z C, Ma Z Y, Fu R K Y, Tian X B, Chu P K, Wu Z Z 2021 Acta Phys. Sin. 70 045202 (in Chinese) [李体军, 崔岁寒, 刘亮亮, 李晓渊, 吴忠灿, 马正永, 傅劲裕, 田修波, 朱剑豪, 吴忠振 2021 70 045202]
[16] Lennon M A, Bell K L, Gilbody H B, Hughes J G, Kingston A E, Murray M J, Smith F J 1988 J. Phys. Chem. Ref. Data 17 1285
[17] Cui S H, Chen Q H, Guo Y X, Chen L, Jin Z, Li X T, Yang C, Wu Z C, Su X Y, Ma Z Y, Fu R K Y, Tian X B, Chu P K Chu, Wu Z Z 2022 J. Phys. D. Appl. Phys. 55 325203
[18] Bultinck E, Kolev I, Bogaerts A, Depla D 2008 J. Appl. Phys. 103 013309
[19] Cui S H, Wu Z Z, Lin H, Xiao S, Zheng B C, Liu L L, An X K, Fu R K Y, Tian X B, Tan W C, Chu P K 2019 J. Appl. Phys. 125 063302
[20] Bogaerts A, Bultinck E, Kolev I, Schwaederle L, Van A K, Buyle G, Depla D 2009 J. Phys. D: Appl. Phys. 42 194018
[21] Cui S H, Guo Y X, Chen Q H, Jin Z, Yang C, Wu Z C, Su X Y, Ma Z Y, Tian X B, Wu Z Z 2022 Acta Phys. Sin. 71 055203 (in Chinese) [崔岁寒, 郭宇翔, 陈秋皓, 金正, 杨超, 吴忠灿, 苏雄宇, 马正永, 田修波, 吴忠振 2022 71 055203]
[22] Samuelsson M, Lundin D, Jensen J, Raadu M A, Gudmundsson J T, Helmersson U 2010 Surf. Coat. Tech. 205 591
[23] Cui S H, Wu Z Z, Xiao S, Chen S, Li T J, Liu L L, Fu R K Y, Tian X B, Chu P K, Tan W C 2019 Acta Phys. Sin. 68 195204 (in Chinese) [崔岁寒, 吴忠振, 肖舒, 陈磊, 李体军, 刘亮亮, 傅劲裕, 田修波, 朱剑豪, 谭文长 2019 68 195204]
[24] Park D H, Kim J H, Ermakov Y 2008 Rev. Sci. Instrum. 79 02B312
[25] Gui B, Yang L, Zhou H, Luo S, Xu J, Ma Z, Zhang Y 2022 Vacuum. 200 111065
[26] Ziegler J F, Ziegler M D, Biersack J P 2010 Nucl. Instrum. Methods Phys. Res. B 268 1818
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