电-磁场协同增强HiPIMS技术的CrAl靶放电行为及CrAlN薄膜制备EI北大核心CSCD

基于常规高功率脉冲磁控溅射(HiPIMS)存在的问题,发展了新型HiPIMS放电模式:电-磁场协同增强高功率脉冲磁控溅射((E-MF)HiPIMS)。研究新型放电模式下CrAl靶的放电行为及CrAlN薄膜的沉积特性。结果表明,不同工作气压下,CrAl靶放电电流波形随靶脉冲电压的变化规律相似。随脉冲电压的增大,CrAl靶脉冲峰值电流线性增加,随着氮气流量的增大,CrAl靶脉冲峰值电流线性增加,随着复合直流的增大,CrAl靶电流上升速度不变但靶脉冲峰值电流出现明显降低。与常规HiPIMS相比,(E-MF)HiPIMS技术制备的CrAlN薄膜表面更加光滑、平整,且表面粗糙度仅为4.123 nm。CrAlN薄膜的生长结构更加致密而紧凑,晶粒也更加细小、均匀。此外,(E-MF)HiPIMS技术制备的CrAlN薄膜样品的摩擦因数显著降低,且磨损后的磨痕宽度小、磨损处仅出现间断型的表面磨损,摩擦磨损性能更加优异。同时样品的腐蚀电位较大提高、腐蚀电流大幅减小,表现出更优异的耐腐蚀性能。     

高功率脉冲磁控溅射等离子体放电特性研究现状

高功率脉冲磁控溅射(HiPIMS)因其较高的靶材原子离化率和优异的薄膜成形性能,逐渐成为PVD领域的热点镀膜技术。靶材原子的高度离化宏观表现为较大的放电电流。介绍了等离子体放电靶电流的构成及其形成原理,分析了HiPIMS放电过程中磁场、靶电压、工作气压对靶材原子离化率的影响,及其相应放电靶电流曲线。空间磁场可以束缚电子,增长靶前电子运动轨迹,同增大工作气压一样,都可以减小粒子运动平均自由程,增大粒子碰撞几率,提高原子离化率,增大放电靶电流。升高靶电压可以提高离子碰撞能量,靶电压越高,放电靶电流越大。分析了各种靶材在不同电压下的放电靶电流曲线。优异的薄膜成形性能得益于对离子运动的良好控制,阐述了等离子体空间电荷分布状况、靶材自溅射和"气体循环"过程、二次电子发射及其促进离化机制、等离子体碰撞引起的气体稀薄现象,以及预鞘层对二次电子和等离子体电子的焦耳加热效应等微观机理,论述了这些微观机理对粒子离化的作用效果。最后展望了研究HiPIMS等离子体放电特性可能的研究方向。     

不同靶材料的高功率脉冲磁控溅射放电行为

选择具有不同溅射产额的靶材料(Cu,Cr,Mo,Ti,V和C),研究了其高功率脉冲磁控溅射(HPPMS)放电靶电流波形随靶电压的演化行为.发现所有材料都满足5个阶段顺序放电特征,但是不同溅射产额的材料的相同放电阶段所需要的靶电压呈现先增加后下降的趋势,根据放电难易的不同分别表现出一定阶段的缺失.对其靶电流平均值、峰值和平台值的统计显示,溅射产额高的靶材料自溅射容易,平台稳定,对靶电流的贡献主要为平台值(金属放电),比较适用于HPPMS方法沉积薄膜;而溅射产额低的靶材料气体放电明显,靶电流主要由峰值(气体放电)贡献,不利于薄膜沉积.     

不同靶基距下凹槽表面HIPIMS法制备钒膜的微观结构及膜厚均匀性

目的研究不同靶基距对高功率脉冲磁控溅射(HIPIMS)在凹槽表面制备钒膜微观结构和膜厚均匀性的影响,实现凹槽表面高膜层致密性和均匀性的钒膜制备。方法采用HIPIMS方法制备钒膜,在其他工艺参数不变的前提下,探讨不同靶基距对凹槽表面钒膜相结构、表面形貌及表面粗糙度、膜层厚度均匀性的影响。采用XRD、AFM及SEM等观测钒膜的表面形貌及生长特征。结果随着靶基距的增加,V(111)晶面衍射峰强度逐渐降低。当靶基距为12 cm时,钒膜膜层表面粗糙度最小,为0.434nm。相比直流磁控溅射(DCMS),采用HIPIMS制备的钒膜呈现出致密的膜层结构且柱状晶晶界不清晰。采用HIPIMS和DCMS方法制备钒膜时的沉积速率均随靶基距的增加而减少。当靶基距为8 cm时,采用HIPIMS方法在凹槽表面制备的钒膜均匀性最佳。结论采用HIPIMS方法凹槽表面钒膜生长的择优取向、表面形貌、沉积速率及膜厚均匀性均有影响。在相同的靶基距下,采用HIPIMS获得的钒膜膜厚均匀性优于DCMS方法。     

双脉冲HiPIMS放电特性及CrN薄膜高速率沉积

提出了一种新型的高功率脉冲磁控溅射(HiPIMS)技术,即放电由脉宽短、电压高的引燃脉冲和脉宽长、电压低的工作脉冲2部分组成的双脉冲高功率脉冲磁控溅射技术,目的是解决传统高功率脉冲磁控溅射沉积速率低的问题。研究了引燃脉冲电压及传统高功率脉冲磁控溅射条件对Cr靶在Ar气气氛下的放电特性的影响,并制备CrN薄膜。结果表明:随着引燃脉冲电压的施加,双脉冲高功率脉冲磁控溅射Cr靶放电瞬间建立,并获得较高的峰值电流,而传统HiPIMS模式的输出是渐渐爬升的三角波电流;与传统高功率脉冲磁控溅射相比,单位功率下双脉冲高功率脉冲磁控溅射具有更高的基体电流积分以及更多的Ar~+和Cr~0数量;引燃脉冲电压为590 V时,双脉冲高功率脉冲磁控溅射单位功率下CrN薄膜沉积速率为2.52μm/(h·kW),比传统高功率脉冲磁控溅射提高近3倍。     

脉冲放电强度对磁控溅射Cr薄膜微观结构的影响

在脉冲非平衡磁控溅射环境中,通过提高脉冲靶电压(分别为600、700及800 V)使工作气体Ar获得3种不同强度的异常辉光放电状态(单脉冲峰值靶功率密度分别为10、30及70 W/cm2),并分别制备Cr薄膜.利用SEM、AFM、XRD及TEM等方法研究、比较了非平衡磁控溅射Cr薄膜的微观结构在不同Ar气脉冲异常辉光放电强度条件下的差异.结果表明,随Ar气脉冲异常辉光放电强度的增强:Cr薄膜沉积速率显著提高,薄膜表面粗糙度略有增大,但表面颗粒未出现长大现象,且尺寸均匀、细小,择优生长的Cr(110)晶面的衍射峰强度明显降低,结晶效果逐渐降低.不同异常辉光放电强度条件下制备的Cr薄膜均以柱状方式生长,微观组织呈现出纳米级尺度的晶粒(直径5 ～ 10 nm)镶嵌式分布的形态.     

大尺寸平面磁控靶高功率脉冲放电的近基底表面光谱研究

目的探索高功率脉冲磁控溅射方法在大尺寸平面磁控溅射Cr靶过程中,近基底表面等离子体区域内的活性粒子分布特性以及辐射跃迁过程,为HiPIMS的规模化应用提供实验基础和理论依据。方法选择不同高功率脉冲溅射脉冲电压、工作气压和耦合直流等关键沉积参数,采用等离子体发射光谱仪测量近基底表面等离子体区域内的光学发射光谱,分析原子特征谱线的种类、强度分布、离子谱线强度百分比、金属原子谱线含量等。结果当脉冲电压到达700 V后,基底表面的等离子体区域内的金属离化率显著提高;脉冲电压为600 V时,适当增加工作气压至5.0 mTorr,能有效提高到达基底的Cr激发态粒子含量,工作气压的升高会降低金属离化率。增加耦合直流在一定程度上降低了能到达基底的活性Cr~+和Cr~*原子含量,为了保持一定的活性粒子比例,耦合直流应当小于1.0 A。结论大面积高功率脉冲磁控溅射中的近表面等离子体区域内的主要活性粒子为Ar~+和Cr~*激发态原子,其主导的碰撞过程为Ar~+的电离复合过程和Cr~*的退激发过程,金属离化率还有待提高。     

不同电场环境对镀料脱靶方式及TiN镀层微观结构的影响

当前主流的镀层沉积技术中,电弧离子镀因镀料熔融喷溅脱靶致镀料中夹杂微米尺度高温颗粒,易使镀层表面粗糙和基体高温损伤;直流磁控溅射因镀料碰撞溅射脱靶致离化率低,易使镀层厚度不均和组织疏松。为解决以上技术缺点,依据气体放电等离子体物理学知识,采用新型阶梯式双级脉冲电场诱发阴极靶材与阳极腔体间气体微弧放电,依靠微弧放电后产生的高密度等离子体,增强Ar+对靶面的轰击动能和靶面产生的焦耳热,实现镀料由碰撞溅射脱靶向热发射脱靶的转变,并以此提高镀料的离化率,达到改善镀层结构的目的。实验结果表明：双级脉冲电场诱发的气体微弧放电呈现出耀眼白光,而靶面形貌则表现出高低起伏的凹坑和水流波纹,其靶面形貌不同于镀料碰撞溅射脱靶后的多边形凹坑,说明靶面局部区域的镀料以热发射方式脱靶。同时,在双级脉冲电场下制备的TiN镀层具有较为致密的组织结构,沉积速率可达51nm/min。     

不同Ti靶电流对Ti掺杂类石墨碳膜的结构和性能的影响(英文)

利用磁控溅射的方法成功制备Ti掺杂类石墨碳(Ti-GLC)膜。采用拉曼光谱、X射线光电子谱(XPS)、扫描电子显微镜(SEM)、原子力显微镜(AFM)、纳米压痕仪和球盘式摩擦机分别表征不同Ti靶电流下制备的Ti-GLC膜的成分、结构和性能。随着Ti靶电流的增加,薄膜中sp2键的比率和Ti含量增加,同时薄膜的硬度和内应力也增大,但较高的Ti靶电流将会促使薄膜产生鳞片状结构从而使其变疏松。较少的Ti掺入量可以降低GLC膜的干摩擦因数,纯GLC膜在水润滑条件下的摩擦因数最低。在较低Ti靶电流下制备的Ti-GLC膜在干摩擦及水润滑条件下均具有较高的抗磨性能。     

磁控溅射法制备W-Cu薄膜的研究

采用W70Cu30单靶磁控溅射与纯W、纯Cu双靶磁控共溅两种工艺,在多种基材上制备W-Cu薄膜,分析了薄膜的宏观形貌和组织结构.分析结果表明:单靶磁控溅射时,控制靶电压520 V,溅射电流0.8～1.2A,Ar气流量25 mL/min(标准状态),可在玻璃基体上镀得W-Cu薄膜,但退火时如温度过高,会使W和Cu两种元素原子偏聚加重;双靶磁控溅射时,控制Ar气流量20 mL/min(标准状态),Cu靶电流0.7A,W靶电流1.2A,溅射时间3600 s,可在硅基和玻璃基上镀得W-Cu薄膜,但在石墨基体、陶瓷基体及45钢基体上的镀膜效果不理想.     

EFFECT OF Ar PRESSURE ON STRUCTURAL AND ELECTRICAL PROPERTIES OF Cu FILMS DEPOSITED ON GLASS BY DC MAGNETRON SPUTTERING

Cu films with thickness of 630-1300nm were deposited on glass substrates without heating by DC magnetron sputtering in pure Ar gas. Ar pressure was controlled to 0.5, 1.0 and 1.5Pa respectively. The target voltage was fixed at 500V but the target current increased from 200 to 1150mA with Ar pressure increasing. X-ray diffrac-tion, scanning electron microscopy and atomic force microscopy were used to observe the structural characterization of the films. The resistivity of the films was measured using four-point probe technique. At all the Ar pressures, the Cu films have mixture crystalline orientations of [111], [200] and [220] in the direction of the film growth. The film deposited at lower pressure shows more [111] orientation while that deposited at higher pressure has more [220] orientation. The amount of larger grains in the film prepared at 0.5Pa Ar pressure is slightly less than that prepared at 1.0Pa and 1.5Pa Ar pressures. The resistivities of the films prepared at three different Ar pressures re     

Discharge physics of high power impulse magnetron sputtering

High power impulse magnetron sputtering (HIPIMS) is pulsed sputtering where the peak power exceeds the time-averaged power by typically two orders of magnitude. The peak power density, averaged over the target area, can reach or exceed 10⁷ W/m², leading to plasma conditions that make ionization of the sputtered atoms very likely. A brief review of HIPIMS operation is given in a tutorial manner, illustrated by some original data related to the self-sputtering of niobium in argon and krypton. Emphasis is put on the current–voltage–time relationships near the threshold of self-sputtering runaway. The great variety of current pulse shapes delivers clues on the very strong gas rarefaction, self-sputtering runaway conditions, and the stopping of runaway due to the evolution of atom ionization and ion return probabilities as the gas plasma is replaced by metal plasma. The discussions are completed by considering instabilities and the special case of “gasless” self-sputtering.     

复合高功率脉冲磁控溅射技术的研究进展

高功率脉冲磁控溅射技术(HIPIMS)是一门新兴的高离化率磁控溅射技术.概述了HIPIMS的技术优势,包括高膜层致密度和平滑度、高膜基界面结合强度以及复杂形状工件表面膜层厚度均匀性好等.同时归纳了HIPIMS存在的问题,包括沉积速率及低溅射率金属靶材离化率低等.在此基础上,重点综述了近年来复合HIPIMS技术的研究进展,其中复合其他物理气相沉积技术的HIPIMS,包括复合直流磁控溅射增强HIPIMS、复合射频磁控溅射增强HIPIMS、复合中频磁控溅射增强HIPIMS、复合等离子体源离子注入与沉积增强HIPIMS等;增加辅助设备或装置的HIPIMS,包括增加感应耦合等离子体装置增强HIPIMS、增加电子回旋共振装置增强HIPIMS,以及增加外部磁场增强HIPIMS等.针对各种形式的复合HIPIMS技术,分别从复合HIPIMS技术的放电行为、离子输运特性,及制备膜层的结构与性能等方面进行了归纳.最后展望了复合HIPIMS技术的发展方向.     

The effect of Ti sputter target oxidation level on reactive High Power Impulse Magnetron Sputtering process behaviour

This paper investigates the effect of sputter target oxidation level on reactive process behaviour during High Power Impulse Magnetron Sputtering of transition metal target (Ti) in Ar/O₂ atmosphere. It was found by this study that the sputter target state depends on the history of its use in reactive HIPIMS mode. The effect appears to be pronounced strongly due to the significance of ion irradiation induced effects leading to enhanced sputter target oxidation. The target sputter cleaning times (e.g. after a reactive deposition run) are long (compared to DC sputtering) due to the same reason. The abovementioned effect has serious implications for the hysteresis behaviour and reactive deposition process window. It is shown in this paper that the hysteresis loop can be artificially suppressed or even eliminated and the reactive deposition process window can be reduced a number of times if the starting target surface is not a clean metal surface but a partially oxidised metal surface. Such target surface condition is readily obtainable for the targets that have a history of prolonged use in reactive HIPIMS mode. Processing parameters, such as pulse frequency and peak voltage pulse values are shown to have influence on the degree to what the abovementioned effects occur.     

高离化率物理气相沉积涂层的研究进展

高离化率物理气相沉积是一种新发展起来的脉冲磁控溅射技术(HPPMS),具有溅射靶材原子高度离化与峰值功率超过平均功率等特点。它作为一种新型的离子化物理气相沉积技术,在国内外已经成为一个研究热点,其离子体特性、涂层工艺、高功率脉冲放电等备受国内外学者关注。沉积过程中,离子随着电子碰撞与电荷交换发生电离,并按照双极性扩散理论进行传递。在不同工作气压条件下,离子能量分布表现出不同的特点。在放电过程中使用高的峰值功率脉冲(超出一般沉积技术2~3个数量级)与低脉冲占空比(0.5%~10%)实现高电离(50%),从而表现出了优良的结合力,在控制涂层结构与降低涂层的内部压力等方面有相当大的优势。从HPPMS技术制备涂层的应用现状出发,介绍了高离化率物理气相沉积涂层的特点、优势以及在制备复合涂层和涂层界面优化等方面的研究进展。探讨了高离化率物理气相沉积涂层的未来发展趋势,对涂层的应用效果进行了分析。     

Pressure effects on HiPIMS deposition of hafnium films

High power impulse magnetron sputtering (HiPIMS) was studied during the growth of hafnium films at argon pressures ranging from 0.80 to 5.33 Pa with a fixed pulse length (50 μs) and frequency (200 Hz). The effect of inert gas pressure on the plasma conditions and film structure was investigated. The peak target current increased with pressure, but its sensitivity decreased above 2.00 Pa, which corresponded to an increased ratio of ions to neutrals in the plasma. A comparison of plasma characteristics between Hf and Ti HiPIMS growth was made. In addition to pressure, the target currents were affected by the physical properties of the target material, particularly the secondary ionization energy and atomic mass. Sputtering gas rarefaction phenomena were found to be more pronounced for Hf, and as a result, the process characteristics and film properties had a strong interdependence on argon pressure discussed in this study. The microstructure of the hafnium films was analyzed with scanning electron microscopy and X-ray diffraction. When compared to Hf films deposited by dc magnetron sputtering, the HiPIMS process resulted in a decreased grain size and promoted the growth of the (100) orientation in the Hf films. These results demonstrate that Hf HiPIMS sputtering regimes have much stronger dependence on the working gas pressure compared to titanium, and these need to be taken into account to ensure that films are dense and have the desired morphology and crystallographic orientation.