关键词: 高功率脉冲磁控溅射/
筒内放电/
电子阻挡屏极/
磁场补偿
English Abstract
Electromagnetic control and optimization of high power impulse magnetron sputtering discharges in cylindrical source
Cui Sui-Han1,Wu Zhong-Zhen1,
Xiao Shu1,
Liu Liang-Liang1,
Zheng Bo-Cong1,
Lin Hai1,
Ricky K Y Fu2,
Tian Xiu-Bo1,
Paul K2,
Tan Wen-Chang1,
Pan Feng1
1.School of Advanced Materials, Peking University Shenzhen Graduate School, Shenzhen 518055, China;
2.Department of Physics and Materials Science, City University of Hong Kong, Hong Kong 999077, China
Fund Project:Project supported by the National Materials Genome Project, China (Grant No. 2016YFB0700600), the Natural Science Foundation of China (Grant No. 51301004), the Shenzhen Science and Technology Research Grant, China (Grant Nos. JCYJ20140903102215536, JCYJ20150828093127698), and the City University of Hong Kong Applied Research Grant (ARG), China (Grant No. 9667122).Received Date:04 November 2016
Accepted Date:06 February 2017
Published Online:05 May 2017
Abstract:High-power impulse magnetron sputtering (HiPIMS), a new physical vapor deposition technique which combines the advantages of the high ionization rates of the sputtered materials and control of electromagnetism, has been widely used to deposit high-performance coatings with a large density and high adhesion. However, HiPIMS has some intrinsic disadvantages such as the low deposition rate, unstable discharge, and different ionization rates for different materials thereby hampering wider industrial adoption. We have recently designed an optimized cylindrical source based on the hollow cathode effect to circumvent the aforementioned limitations. However, during the operation of the cylindrical source, the discharge is inhomogeneous and the etching stripes are nonuniform. In order to determine the underlying mechanism and optimize the electromagnetic control, the discharge in the HiPIMS cylindrical source is simulated. The tangential magnetic field distribution on the target surface of the cylindrical sputtering source is inhomogeneous and electron runaway is serious, resulting in a relatively low plasma density. Two solutions are proposed to improve the situations. The first one is electrical improvement by installing an electron blocking plate, and the second one is magnetic improvement by adding compensating magnets. Our simulation results of the first method show that a potential well is produced by the electron blocking plate to suppress electron runaway and the plasma density is improved significantly, especially around the central cross-section of the cylindrical sputtering source. The discharge becomes homogeneous, and the etching stripes are uniform albeit not full enough. The second method of magnetic improvement significantly improves the homogeneity of the tangential magnetic field distribution on the target surface and the target utilization rate. After adding the optimized compensating magnets, the shape of the effective area (the value of the tangential magnetic field in a range of 25-50 mT) on the target surface can be controlled and made zonal. The target utilization rate increases to over 80% from 60%. In order to obtain the optimal conditions, the two techniques are combined. A larger and more homogeneous etching ring is observed by adopting both the electrical and magnetic improvements as predicted and explained by the simulation results. It can be concluded that the combination of the two improvement techniques can improve and optimize the HiPIMS cylindrical source.
Keywords: high power impulse magnetron sputtering/
discharge in cylindrical source/
electron blocking plate/
magnetic field compensation
