高功率脉冲磁控溅射(HiPIMS)过程特征的物理解析

Physical Analysis of Plasma Features in High Power Impulse Magnetron Sputtering(HiPIMS)Discharges

高功率脉冲磁控溅射(HiPIMS)作为一种新的物理气相沉积技术,得到学术界和工业界的广泛关注。HiPIMS中靶峰值能量密度高而平均能量密度低,从而避免了传统磁控溅射中靶过热所导致的靶材融化等问题。独特的放电特性使得HiPIMS具有高等离子体密度和电离率,为控制沉积粒子能量和输运模式提供了可能性,可以实现高质量薄膜的制备。本文综述了HiPIMS系统的电源特性(与脉冲发生相关)、放电参数(脉宽、放电电压、电流、频率等)和放电空间(分为阴极靶和鞘层区、电离区域、体等离子体区、以及阳极等离子体和衬底区)中所涉及放电特征的物理本质及其解析,这将有助于加强对HiPIMS技术物理机制的深入理解,推进该技术在实际工业中的应用。

As a promising physical vapor deposition(PVD)technique,high power impulse magnetron sputtering(HiPIMS)attracts widespread attention both in academic and industrial fields. The energy density with a low average value but high peak value at the target featured for HiPIMS avoids the issue of target melting by overheating. In addition,the unique discharge characteristic endows HiPIMS with high plasma density and ionization fraction of the sputtered vapor,which enables better control of energy and motion of the deposition species. Consequently,multifunctional thin films with high quality could be deposited and applied in multiple industrial applications.The HiPIMS discharge accordingly has been successfully introduced into a variety of industrial fields. In this review,the power characteristics and pulse generator of HiPIMS have been addressed. The pulse parameters,including discharge voltage,current,and pulse length,have been systematically discussed. Finally,the physics and properties of four different discharge regions(i.e.,cathode target and sheath region,ionization region,bulk plasma region,as well as anode plasma and substrate region)involved in the process of HiPIMS discharge have been reviewed in-depth. This work is beneficial to deepen the physical understanding of HiPIMS and further broaden its practical applications.