Magnetic Properties and Growth Behavior of Nd–Fe–B Films on Si(111)
Magnetic Properties and Growth Behavior of Nd–Fe–B Films on Si(111)
复制标题
Si(111) 上 Nd-Fe-B 薄膜的磁性能和生长行为
DOI：
10.1143/jjap.38.4051
复制
发表时间：
1999
影响因子：
1.5
通讯作者：
Shi
中科院分区：
文献类型：
--
作者：
J. Tsai;T. Chin;Shi
用直流磁控溅射法在Si（111）上于600 ~ 700°C制备NdFeB薄膜。在衬底温度为650°C时，以W、Mo或Pt为衬底，在Si（111）上制备了剩磁比大于0.67、本征矫顽力大于7 kOe的各向异性薄膜。机械抛光可使薄膜厚度从850 nm减小到150 nm，薄膜的矫顽力保持在2-5 kOe。通过适当的模型，可以用薄膜中畴壁的运动来解释薄膜厚度对磁化率的强烈依赖性。利用二次离子质谱（西姆斯）和高分辨透射电子显微镜研究了不同衬底上薄膜的深度分布和微观结构。Pt底层，实际上是Pt/Ti/SiO2/Si（111），是NdFeB膜和Si（111）之间的声屏障层，使得如西姆斯深度分布所证明的，存在可忽略的相互扩散。在650°C溅射的Mo或W底层薄膜中发现了硅化物的形成。这可以从西姆斯深度分布中的底层和Si（111）之间的重叠区域观察到。定量估算了Nd、Fe、B在Si（111）中的扩散系数。
NdFeB films were prepared by dc-magnetron sputter-deposition onto Si(111) at 600 to 700°C. Anisotropic films with remanence ratio larger than 0.67 and intrinsic coercivity greater than 7 kOe were obtainable at a substrate temperature of 650°C on Si(111) using one of W, Mo, or Pt as the underlayer. The mechanical polishing can reduce the film thickness from about 850 nm to 150 nm, and the coercivity remains 2–5 kOe. The coercivity of being strongly dependent on film thickness can be explained by the domain-wall motion in films through suitable modeling. The depth-profile and microstructure of the films on different underlayers were explored by secondary ion mass spectroscopy (SIMS) and high resolution transmission electron microscopy. The Pt underlayer, being in fact a Pt/Ti/SiO2/Si(111), is a sound barrier layer between the NdFeB film and Si(111) so that there is negligible interdiffusion as evidenced by SIMS depth profile. The formation of silicide was found in films with Mo or W underlayer sputtered at 650°C. This can be observed from the overlap region between the underlayer and Si(111) in the SIMS depth profile. Diffusion coefficients of the Nd, Fe, B in Si(111) were also quantitatively estimated.