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Phase shift effects of radio-frequency bias on ion energy distribution in continuous wave and pulse modulated inductively coupled plasmas 下载免费PDF全文
A retarding field energy analyzer(RFEA) is used to measure the time-averaged ion energy distributions(IEDs) on the substrate in both continuous wave(CW) and synchronous pulse modulated radio-frequency(RF) inductively coupled Ar plasmas(ICPs).The effects of the phase shift θ between the RF bias voltage and the RF source on the IED is investigated under various discharge conditions.It is found that as θ increases from 0 to π,the IED moves towards the low-energy side,and its energy width becomes narrower.In order to figure out the physical mechanism,the voltage waveforms on the substrate are also measured.The results show that as θ increases from 0 to π,the amplitude of the voltage waveform decreases and,meanwhile,the average sheath potential decreases as well.Specifically,the potential drop in the sheath on the substrate exhibits a maximum value at the same phase(i.e.,θ = 0) and a minimum value at the opposite phase(i.e.,θ = π).Therefore,when ions traverse across the sheath region above the substrate,they obtain less energies at lower sheath potential drop,leading to lower ion energy.Besides,as θ increases from π to 2π,the IEDs and their energy widths change reversely. 相似文献
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A self-consistent two-dimensional (2D) collisionless fluid model is developed to simulate the characteristics of a dual frequency capacitive sheath over an electrode with a cylindrical hole. The model consists of 2D time-dependent fluid equations coupled with Poisson's equation, in which the low-frequency (LF) and high-frequency current sources are applied to an electrode. Thus, the so-called equivalent circuit model coupling with the fluid equations will be able to self-consistently determine the relationship between the instantaneous voltage on the powered electrode and the sheath thickness. The time-averaged potential, electric field, ion density in the sheath and ion energy distributions at the bottom of the hole are calculated and compared for different LF frequencies. The results show that the LF frequency is crucial for determining the sheath structure. The existence of the cylindrical hole on the electrode obviously affects the sheath profile in the parallel to the electrode and makes the sheath profile tend to adapt the contours of the electrode, which is the plasma molding effect. 相似文献
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We study characteristics of a single dust particle in a duai-frequency capacitively coupled plasma sheath, such as charging and suspending processes, using a collisionless self-consistent model. Also, the movement of the dust grain with time is investigated for the various radii and initial velocities. The numerical results show that, after several microseconds, the charging process of the dust particle reaches equilibrium, and the grain obtains its equilibrium position, In addition, it is found that the parameters of the low-frequency source impact on the charging and suspending processes of the dust grain significantly. 相似文献
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Influence of ion species ratio on grid-enhanced plasma source ion implantation 总被引:1,自引:0,他引:1 下载免费PDF全文
Grid-enhanced plasma source ion implantation (GEPSⅡ) is a newly proposed technique to modify the inner-surface properties of a cylindrical bore. In this paper, a two-ion fluid model describing nitrogen molecular ions N2^ and atomic ions N^ is used to investigate the ion sheath dynamics between the grid electrode and the inner surface of a cylindrical bore during the GEPSⅡ process, which is an extension of our previous calculations in which only N2^ was considered.Calculations are concentrated on the results of ion dose and impact energy on the target for different ion species ratios in the core plasma. The calculated results show that more atomic ions N^ in the core plasma can raise the ion impact energy and reduce the ion dose on the target. 相似文献
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研究了C20团簇在几种金属氧化物(Al2O3,SiO2)中穿行时发生的库仑爆炸过程.采用线性介电响应理论,并结合Mermin形式的介电函数,得到了团簇中各组成离子的空间感应势,其中组成团簇中各组成离子的电荷分布情况由Brandt-Kitagawa有效电荷理论模型来描述.通过求解运动方程得到离子团结构随时间的演化过程,并采用Monte Carlo方法模拟了爆炸过程中的多重散射现象.我们发现,尾流效应使团簇的空间结构和电荷分布呈现非对称性. 相似文献
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研究了快速双原子分子离子在固体中穿行时,尾流效应对各离子电荷态以及库仑爆炸过程的影响.借助于线性介电响应理论和局域介电函数,离子之间的动力学相互作用势可以表示成对称的屏蔽库仑势和非对称的尾势.通过对分子离子上所有束缚电子的总能量进行变分和求解单个离子的运动方程,自洽地确定出分子离子中每个离子的电荷态.数值结果表明,由于尾流效应的影响,在初始穿行阶段,分子离子中导航离子的电荷数随穿行深度的增加而单调递增,而尾随离子的电荷数则随穿行深度的增加而振荡.但当穿行深度很大时,两个离子的电荷数都趋于具有相同速度的孤立离子的电荷数.此外,还发现分子轴的取向朝入射速度方向偏转 相似文献
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用Langmuir探针对射频(13.56 MHz)感应等离子体进行了诊断,给出了Ar等离子体轴向和径向参数随气压的变化。采用发射光谱测量了等离子体中氩原子的750.3nm谱线强度随气压在轴向的变化,其变化趋势与Langmuir探针测量结果的变化趋势相一致。测量了氩离子的434.8nm谱线强度随气压在轴向的变化并获得了氩离子的434.8nm谱线强度与氩原子的430.0nm谱线强度的比值在轴向三个不同位置的变化。从测得的结果可知:在放电室中上部形成了均匀稳定的高密度等离子体,在靶附近有所降低,在中部以下等离子体密度逐渐变低;在径向6~7 cm以内的区域等离子体参数变化不大,形成了均匀稳定的等离子体,等离子体参数在器壁处变化明显。 相似文献
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利用自主研制的全悬浮双探针, 对影响双频容性耦合等离子体径向均匀性的因素进行了研究. 发现低频功率、放电气压和放电间距对径向均匀性有明显影响. 合适的低频功率、放电气压及较大的极板间距可以得到更均匀的等离子体. 采用与实验相同的放电参数, 利用改进的二维流体模型进行理论模拟, 得到了不同极板间距下径向离子密度分布, 并和实验测量结果进行了比较, 两者的变化趋势基本符合.
关键词:
双频容性耦合等离子体
径向均匀性
全悬浮双探针
二维流体模型 相似文献