Ni/Ti多层膜界面状态优化分析

Optimizing Analysis of Interface State of the Ni /Ti Multilayer Films

目的减小Ni/Ti多层膜表面粗糙度,提高Ni/Ti多层膜对中子束的反射率。方法采用离子束辅助沉积设备沉积Ni/Ti周期性多层膜,通过不同抛光时间和不同离子能量轰击对多层膜界面进行清洗抛光;采用反应溅射法,在镀Ti层时使用氢气和氩气混合气为工作气体,将H原子掺入Ti层以改变晶粒结构而影响多层膜界面状态。结果随着辅助离子源功率的增加,Ni/Ti多层膜的表面粗糙度增加;在合适的离子能量下,随着抛光时间的不断增加,Ni/Ti多层膜的表面粗糙度逐渐减小。Ti层中掺H的Ni/Ti多层膜比未掺H的多层膜表面粗糙度小,界面更加清晰。结论低能量的离子轰击条件下,适当的抛光时间能对多层膜实现较好的抛光效果。Ti层中掺入H原子,抑制了Ni原子与Ti原子的扩散,减小了Ti膜层晶粒大小,从而抑制了表面粗糙度的增加。

Objective To reduce the interface roughness of the Ni/Ti multilayer film, and improve the neutron reflectivity of the multilayer. Methods A series of Ni/Ti periodic multilayers were fabricated by the ion beam assisted deposition device, and the Ni/ Ti muhilayers were rinsed and polished though bombarding by ion beam with different ion energy and polishing time. The Ni/Ti multilayers was deposited by the reactive sputtering, the argon gas mixed with hydrogen was used as the working gas when the Ti layers were deposited to embed the hydrogen atom into the Ti layers, which can change the grain structure and affect the interface state of Ni/Ti multilayers. Results With the increase of the assisted ion source＇s power, the surface roughness of the Ni/Ti multi- layer films was increased. And under appropriate ion energy condition, with the bombardment time getting longer, the surface roughness of the Ni/Ti multilayers was reduced, the surface roughness of the Ni/Ti multilayers films became smaller and the inter- faces got more distinct when the H atoms were embedded into the Ti layers. Conclusion The interface state of the muhilayer films can get better when impacted by the lower energy ion beam with the suitable time of polishing. The hydrogen atom in the Ti crystal lattice can suppress the diffusion between the Ni and Ti layers, and reduce the grain size thus suppressing the increase in the inter- face roughness.