物理学报2026，Vol.75Issue(15)：263-275,13.DOI:10.7498/aps.75.20260340
双极高功率脉冲磁控溅射阳极电双层的基本特征及其对离子能量的影响
Basic characteristics of anode double layer in bipolar pulse high-power impulse magnetron sputtering and their effects on ion energy
摘要
Abstract
The precise regulation of deposition ion energy is a critical frontier in low-temperature plasma physics and surface modification.Bipolar pulse high-power impulse magnetron sputtering(BP-HiPIMS)has emerged as a promising technology that achieves the acceleration of high-density ion fluxes via a reversed positive pulse.However,the basic characteristics and formation process of the double layer(DL)during the positive pulse and their effects on the energy of deposition ions remain incompletely understood.This study aims to systematically investigate the spatial distribution and temporal evolution of the DL and elucidate the underlying correlations between discharge parameters and ion acceleration mechanisms.A home-built emissive probe system(APD-EP3A)and an energy-resolved mass spectrometer(Hiden PSM003)are synchronously employed to diagnose the BP-HiPIMS discharge with a Cu target.The emissive probe,operating in the saturated electron emission regime,provides a high spatial resolution of～1 mm and a temporal resolution of～200 ns to capture the transient plasma potential(Vp)evolution from the near-target region(z＜25 mm)to the bulk plasma(z=25-80 mm).Specifically,the evolutionary trajectories of the DL structure and the time-averaged ion energy distribution functions(IEDFs)are comprehensively evaluated under varying positive pulse voltages(U+=+150 V and U+=+250 V)and negative pulse widths(τ_=25-200 μs). The spatiotemporal potential mapping reveals that upon the onset of the positive pulse,the near-target plasma undergoes a dynamic physical reconstruction from a quasi-neutral state to a DL structure.Notably,the physical boundary between the high-and low-potential regions appears near the magnetic null point(z=20-25 mm).This spatial anchoring effect exhibits strong physical robustness governed by the cross-field transport resistance of the magnetic mirror topology.Furthermore,the structural reconstruction of the DL generates a steep local spatial potential drop of～20 V,serving as the primary axial acceleration source for traversing ions.Varying the discharge parameters demonstrates distinct regulatory mechanisms on the DL and ion energy.Elevating the positive voltage(U+)not only directly increases the spatial potential drop of the DL boundary but also establishes a clear quantitative correspondence with the high-energy shift of the ion peak in IEDFs.Simultaneously,a higher U+shortens the DL formation time,effectively extending the acceleration time window and thereby increasing the overall proportion of high-energy ions.Conversely,prolonging the negative pulse width(τ-)intensifies the gas rarefaction effect,rendering low-ionization-energy metal atoms the dominant species upon the onset of the positive pulse.While this compositional evolution significantly accelerates the DL formation process,a longer τ-simultaneously allows a massive flux of unaccelerated initial ions to diffuse to the substrate.This dramatically expands the absolute base of low-energy ions,ultimately leading to a monotonic decrease in the relative proportion of high-energy ions. This study provides direct spatial measurement evidence for the highly transient DL structure and physically elucidates the logical chain from microscopic electric field reconstruction to macroscopic ion kinetic energy gain,offering a theoretical foundation for tailoring energetic ion fluxes to deposit superior-performance advanced thin films.关键词
双极高功率脉冲磁控溅射/等离子体电位/电双层/离子能量Key words
bipolar pulsed high-power impulse magnetron sputtering/plasma potential/double layer/ion energy引用本文复制引用
吴亦言,韩明月,罗阳,杨明轩,李刘合..双极高功率脉冲磁控溅射阳极电双层的基本特征及其对离子能量的影响[J].物理学报,2026,75(15):263-275,13.基金项目
中国航空发动机集团产学研合作项目(批准号:HFZL2023CXY014)、国家自然科学基金(批准号:12275014,12305278)、北京市自然科学基金(批准号:L252098,L252037)和电能高密度转换全国重点实验室开放基金(批准号:DN202514)资助的课题. Project supported by the China Aero Engine Corporation(AECC)Industry-Academia-Research Collaboration Program(Grant No.HFZL2023CXY014),the National Natural Science Foundation of China(Grant Nos.12275014,12305278),the Natural Science Foundation of Beijing,China(Grant Nos.L252098,L252037),and the State Key Laboratory of High-Density Electrical Energy Conversion(Grant No.DN202514). （批准号:HFZL2023CXY014）
