Origins of ion energy distribution function (IEDF) in high power impulse magnetron sputtering (HIPIMS) plasma discharge
Origins of ion energy distribution function (IEDF) in high power impulse magnetron sputtering (HIPIMS) plasma discharge
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DOI：
10.1088/0022-3727/41/9/095203
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发表时间：
2008-05
期刊：
影响因子：
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通讯作者：
A. Hecimovic;K. Burcalová;A. Ehiasarian
中科院分区：
文献类型：
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作者：
A. Hecimovic;K. Burcalová;A. Ehiasarian
采用等离子体采样能量分辨质谱法研究了高功率脉冲磁控溅射（HIPIMS）放电中的离子能量分布函数（IEDF）。分析了铬（Cr）、钛（Ti）和碳（C）靶在氩（Ar）气氛中的热等离子体质谱（HIPIMS）。目标和气体的单电荷和双电荷离子被检测到。在距离靶150 mm的基板位置处测量所有检测到的离子的时间平均IEDF。研究了靶电流和放电气压对IEDF的影响。在两个压力和三个峰值放电电流进行测量。目标和气体离子的IEDF被发现包括两个麦克斯韦分布。在低压下对目标IEDF的定量分析表明，主峰具有较低的平均能量，近似值为EAV = 1 eV，这归因于与热化气体原子和离子的碰撞。较高的能量分布具有延伸至70 eV的尾部，其被假定为源自溅射金属原子的汤普森分布，所述溅射金属原子由于碰撞而被热化并且表现为麦克斯韦分布。金属离子的高能量IEDF的比例单调增加作为Id的函数。有效离子温度kBT，提取的主要低能量峰，表现出较弱的依赖于峰值电流。从高能量尾部提取的有效离子温度表现出很强的相关性与Id的变化。在高压下的IEDF表明，高能量IEDF的比例很低，并由低能量主峰为主。高压下的气体IEDF完全热化。发现金属离子与气体离子的比率随着Id和靶材料的溅射产率而增加。
The ion energy distribution function (IEDF) in high power impulse magnetron sputtering (HIPIMS) discharges was studied by plasma sampling energy-resolved mass spectroscopy. HIPIMS of chromium (Cr), titanium (Ti) and carbon (C) targets in argon (Ar) atmosphere was analysed. Singly and doubly charged ions of both the target and the gas were detected. Time-averaged IEDFs were measured for all detected ions at the substrate position at a distance of 150 mm from the target. The effects of target current and discharge pressure on the IEDF were investigated. Measurements were done at two pressures and for three peak discharge currents. The IEDF of both the target and the gas ions was found to comprise two Maxwellian distributions. Quantitative analysis of target IEDFs at a low pressure showed that the main peak had a lower average energy with an approximate value of EAV = 1 eV which is attributed to collisions with thermalized gas atoms and ions. The higher energy distribution has a tail extending up to 70 eV, which is assumed to originate from a Thompson distribution of sputtered metal atoms which, due to collisions, are thermalized and appear as a Maxwell distribution. The proportion of high energy IEDFs for metal ions increases monotonically as a function of Id. The effective ion temperature kBT, extracted from the main low energy peak, showed a weak dependence on peak current. The effective ion temperature extracted from the high energy tail showed a strong correlation with the change in Id. The IEDF at high pressure shows that a proportion of high energy IEDFs was very low and dominated by a low energy main peak. The gas IEDF at high pressure was completely thermalized. The metal-ion-to-gas-ion ratio was found to increase with Id and with the sputtering yield of the target material.