镀料粒子脱靶方式对纯铝镀层微观组织的影响  

Effect of Escape-Target Method of Deposited Particles on Microstructure of Pure Aluminum Coating

作　　者：杨超[1] 王戎 郝娟[1] 王迪 蒋百灵[1] Yang Chao;Wang Rong;Hao Juan;Wang Di;Jiang Bailing(School of Materials Science and Engineering,Xi’an University of Technology,Xi’an 710048,China)

机构地区：[1]西安理工大学材料科学与工程学院,陕西西安710048

出　　处：《稀有金属材料与工程》2021年第1期304-310,共7页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(51571114)。

摘　　要：传统磁控溅射的镀料粒子碰撞溅射脱靶后具有较低的离化率和沉积动能,致使制备的纯金属镀层极易形成带有微空隙的柱状结构,降低了镀层的致密性和膜基结合力。针对此问题,在磁控溅射环境下将阴阳极间的电流提升至气体放电伏安特性曲线中的弧光放电过渡区时,受靶面晶界和缺陷处电子逸出功低于晶粒内的影响,靶面微区会形成电子逸出的自增强效应,并产生弧光放电现象。弧光放电使靶面微区熔融,该区域的镀料粒子将以熔融喷溅的方式脱靶,凭借熔融喷溅的高产额特性提高镀料粒子的碰撞离化率,为实现镀层组织的调控打下基础。实验结果发现:本研究采用高频振荡脉冲电场,在逐步提升靶电流的过程中,靶面的微观形貌会由不规则的凹坑状形貌逐渐转变为圆形熔坑和沟壑状形貌,说明镀料粒子的脱靶方式由碰撞溅射逐渐转变为熔融喷溅。靶电流为2 A时,镀料粒子主要以碰撞溅射脱靶,制备的纯Al镀层呈现出典型的柱状组织,而在柱状组织间存在着微小间隙。靶电流增大至14 A时,镀料粒子以熔融喷溅脱靶为主,大量离化的镀料粒子可在基体偏压电场下加速沉积,提高了镀料粒子的扩散能力,弱化了镀层柱状生长的倾向,易使镀层形成致密的组织。同时,镀层的沉积速率和膜基结合力也会有明显提升。For traditional magnetron sputtering,the sputtered species possess low kinetic energy and ionization rate,resulting in the metal coating of columnar structure with micro pores.The coating therefore has poor compactness and adhesion strength.Aiming at this problem,the electric current through the anode and cathode was adjusted to the quantity belonging to the arc discharge transition region between the glow region and arc region of the gas discharge voltammetry curve in plasma physics.The escape energy of electron at the grain boundary and defect of the target is lower than that inside the grain,then the“self-enhancing effect”of electron escape is formed in grain boundary which induces the arc discharge phenomenon.Arc discharge melts some micro regions of the target surface,and the plating particles in these regions leave the target in the form of melt splashing.The high yield of melt splashing can improve the collisional ionization ratio of the plating particles,which establishes a foundation for the control of the coating structure.Results show that in the high frequency oscillating pulsed electric field,when the target current gradually increases,the micro-morphology of the target surface gradually changes from irregular pit-like morphology to round pit and curved ravine morphology,indicating that the off-target mode of the plating material changed from collision sputtering to melt splashing.When the target current is 2 A,the species leave the target by means of collision sputtering.The microstructure of the aluminum coating presents typical columnar structure with voids.When the target current increases to 14 A,the off-target mode of the target particles is mainly melt splashing.Massive ionized plating particles are accelerated under the negative bias of substrate.These ions with high kinetic energy enhance bulk diffusion and weaken the tendency of column growth,which helps the coating form a dense structure.At the same time,the adhesion and the deposition rate of the coating also significantly improve.

关 键 词：磁控溅射 Al镀层 熔融喷溅 组织调控 沉积速率 

分 类 号：TG174.444[金属学及工艺—金属表面处理]