高功率脉冲磁控溅射技术的离子(粒子)特性及其对薄膜组织结构的影响

作为电离物理气相沉积法(I-PVD)家族的新成员,高功率脉冲磁控溅射技术(HPPMS/HiPIMS)由于其较高的电子密度及金属离化率,自发现以来即受到了国内外专家的广泛关注。从高功率脉冲磁控溅射过程中金属离化率的角度出发,对高功率脉冲磁控溅射技术的离化机制、离化率定义进行了概述。在此基础上,重点综述了近些年来常用的离化率测量方法,包括等离子体发射光谱法、原子吸收光谱法、质谱仪法、多栅式石英微天平法、正电压沉积法等,并比较了各方法之间的优劣。进一步归纳了影响离化率的关键因素,如靶材功率、脉宽、频率、占空比、峰值电流等电学参数以及靶材种类、气体压力、磁场等非电参数。最后,针对离化率对薄膜性能的影响等方面的研究进展进行了综述,分别讨论了离化率对薄膜组织结构、斜入射沉积及均一性的影响,并概述了离化率对薄膜性能的不利影响。该文旨在为更好地调控并优化溅射过程中的离子特性提供借鉴,为制备性能优异的薄膜提供理论基础。

The Plasma Characteristics in High Power Pulsed Impulsed Magnetron Sputtering (HiPIMS) and Its Effect on Films Properties

As a new member of ionized physical vapor deposition (I-PVD) family, high power pulsed magnetron sputtering (HPPMS/HiPIMS) technology has drawn much attention from experts at home and abroad after being discovered due to highelectron density and metal ionization rate. Ionization mechanism and definition of ionization rate of the technology were summarized from the perspective of metal ionization rate in the process of high power pulsed magnetron sputtering. On this basis, measuring methods of ionization rate which were commonly used in recent years were reviewed, including plasma emission spectrometry, atomic absorption spectrometry, mass spectrometry, multi-gridquartz crystal microbalance, and deposition with positive bias voltage. Advantages and disadvantages of each method were compared. Furthermore, key factors affecting ionization rate were summarized, such aselectrical parameters including target power, pulse width, frequency, duty cycle and peak current, as well as non-electrical parameters including target materials, gas pressure and magnetic field. Finally, the effects of ionization rate on properties of films were reviewed. The effects of ionization rate on microstructure, oblique incidence deposition and homogeneity of the filmswere discussed in detail. The work aims to provide reference for better controllingand optimizing ion characteristics during sputtering and theoretical basis for preparing high-quality films.