磁控溅射ZrN薄膜的生长机理及光学性能

利用直流反应磁控溅射法在Si衬底上沉积了高结晶质量的氮化锆(ZrN)薄膜。采用X射线衍射仪(XRD)、场发射扫描电子显微镜(FE-SEM)、原子力显微镜(AFM)和光谱椭偏仪(SE)研究了沉积时间对ZrN薄膜结构、表面形貌和光学性能的影响。结果表明:所沉积薄膜均为NaCl结构的立方相ZrN,具有(111)面单一取向;沉积时间的增加提高了薄膜的结晶质量;ZrN薄膜的表面形貌、晶粒尺寸以及表面粗糙度随沉积时间发生变化,沉积45 min的薄膜表面出现致密的三角锥晶粒,且表面粗糙度最大,薄膜呈柱状生长。随后利用Extend Structure Zone Model解释了ZrN薄膜的生长机制,最后研究了ZrN薄膜的光反射特性,发现反射光谱与晶粒形状和表面粗糙度密切相关,表面具有三角锥状晶粒的薄膜,其反射谱在300~800 nm波长范围内存在振荡现象,相比于具有不规则晶粒形貌的薄膜其反射率明显下降。本文中研究的生长条件与晶体结构、微观形貌和光学性能之间的关系,可为器件中应用的ZrN薄膜最佳制备条件的优化提供重要的参考价值。

Growth Mechanism and Optical Properties of ZrN Films by Magnetron Sputtering

In this work, zirconium nitride (ZrN) films with high crystalline quality were deposited on Si (111) substrates by direct current magnetron reactive sputtering. The effect of deposition time on the structural property, surface morphology and optical property of the ZrN films were investigated by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), atomic force microscope (AFM) and spectroscopic ellipsometry (SE). The results confirm that all the ZrN films have a cubic, NaCl-type crystal structure with (111) single orientation and the crystalline quality of the films increase with the increasing deposition time. The surface morphology, grain size and surface roughness of ZrN films change with deposition time. A dense columnar structure with triangular pyramid-shaped grains is observed when the deposition time increased to 45 min. Subsequently, the growth mechanism of ZrN films was explained using Extend Structure Zone Model. Finally, the reflection characteristics of ZrN films were studied. It is found that the reflectivity decrease when the film has a triangular pyramid texture, compared with that of none texture counterparts. Moreover, with increasing deposition time to 45 min, there are oscillations in the reflectance spectrum with the wavelength range of 300~800 nm, which did not occur in the films with shorter deposition time. The correlations between growth conditions, crystal structure, microstructure as well as optical properties, could provide an important reference value for optimum conditions to produce ZrN films for utilization in devices applications.