Progress and impact of magnetic field application during pulsed laser deposition (PLD) on ceramic thin films
Progress and impact of magnetic field application during pulsed laser deposition (PLD) on ceramic thin films
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DOI：
10.2109/jcersj2.17150
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发表时间：
2017-12-01
影响因子：
1.1
通讯作者：
Suzuki, Hisao
中科院分区：
文献类型：
--
作者：
Wakiya, Naoki;Kawaguchi, Takahiko;Suzuki, Hisao
当聚焦的激光束照射到目标上时，电子和阳离子从目标发射出来，形成羽流（等离子体）。这种现象被称为激光烧蚀（LA）。使用激光烧蚀的薄膜沉积方法被称为脉冲激光沉积（PLD）。电子和阳离子的复合通常发生在羽流中，然后它们到达衬底形成薄膜。然而，先前的报告表明，对羽流施加磁场抑制了重组并增强了电子冲击激发。因此，在PLD期间，电子和阳离子的通量可以由外部磁场控制。带电阳离子可以从中性粒子或重簇（如液滴）中分离出来。这一原理已被用于获得无液滴的薄膜。对羽流施加磁场也会引起欧姆加热并抑制绝热膨胀。因此，有磁场作用的羽流中的电子温度比没有磁场作用的羽流中的电子温度高。这一原理已被用于降低结晶温度，改善结晶度，提高薄膜性能。由于施加磁场抑制复合和增强电子冲击激发，羽流中存在几个阳离子。然后它们冲向底物。这一原理产生了生长方式的变化，从而导致了薄膜形态的变化。此外，这一原理导致相分离控制。据报道，阳离子的撞击使扩散活化能降低，从而导致旋多分解相分离。当组成波在一个方向上传播时，形成具有自发超晶格结构的薄膜，而当形成交联微观结构时，组成波的传播方向是随机的。本文综述了在沉积过程中施加磁场的影响。(c) 2017日本陶瓷学会。版权所有。
When a focused laser beam is irradiated onto a target, electrons and cations are emitted from the target to form a plume (plasma). This phenomenon is referred to as laser ablation (LA). The thin film deposition method using laser ablation is referred to as pulsed laser deposition (PLD). Recombination of electrons and cations usually occurs in the plume before they arrive at a substrate to form a thin film. However, previous reports show that applying a magnetic field to the plume suppresses recombination and enhances electron-impact excitation. The flux of electrons and cations can therefore be controlled by an external magnetic field during PLD. Charged cations can separate from neutral particles or heavy clusters such as droplets. This principle has been used to obtain droplet-free thin films. Applying a magnetic field to the plume also causes ohmic heating and suppression of adiabatic expansion. The electron temperature in a plume with magnetic field application is therefore higher than that in a plume without magnetic field application. This principle has been used to lower crystallization temperatures, improve crystallinity, and enhance thin film properties. Because application of a magnetic field suppresses recombination and enhances electron-impact excitation, several cations exist in the plume. These then rush to the substrates. This principle produces changes the growth mode, which in turn brings about changes in the thin film morphology. Furthermore, this principle leads to phase separation control. The impingement of cations reportedly brings about lowering of the activation energy for diffusion, which leads to phase separation by spinodal decomposition. A thin film with a spontaneous superlattice structure forms when compositional wave propagation occurs in one direction, but when a cross-linked microstructure is obtained the compositional wave direction of propagation is random. This review presents the influence of application of a magnetic field during deposition. (c) 2017 The Ceramic Society of Japan. All rights reserved.