基于几何相位分析的Nb/Si{111}界面应变研究

Study on interface strain of Nb/Si{111} based on geometric phase analysis

本文使用高分辨透射电镜(HRTEM)成像和几何相位分析,研究不同溅射气压制备的铌薄膜/硅基体的界面微观结构和应变状态。研究结果表明:铌薄膜表面由花瓣状层片组织构成,层片组织随机分布,没有明显的特征取向;随着溅射气压的增大,层片尺寸随之增大,致密度减小,出现了大量孔隙,铌薄膜和硅基体之间产生铌、硅元素的混合层;随着溅射气压的增大,硅基体中应变的大小和方向均不相同,溅射气压对硅基体的应变状态具有很大影响;硅基体的应变主要来自于界面混合层和铌薄膜的作用,混合层中铌原子和硅原子相互混杂,存在大量结构缺陷,产生本征应力,从而导致硅基体中产生应变。

In this paper,high resolution electron microscopy imaging and geometric phase analysis were employed to study the microstructure and strain states of Nb/Si interface prepared at different sputtering pressures. The results show that the surface of Nb thin film consists of petals-shape lamellas with random morphological distribution and no obvious characteristic orientation. The size of lamella increases and the density of lamella decreases with the increase of deposition pressure. In the meanwhile,a large number of pores appear on the surface of Nb film and a mixed layer of Nb and Si is generated between the Nb film and Si substrate. The magnitude and direction of strain in the Si substrate change with the increase of disposition pressure. The strain states of Si substrate are tremendously influenced by the disposition pressure. The strain states of Si substrate are mainly produced by the effect of the interfacial mixed layer and the Nb thin film. A large number of structure defects are generated in the mixed layer of Nb and Si,which produces intrinsic stress in the mixed layer,and further results in the formation of strain in the Si substrate.