磁控溅射制备碳化硼薄膜的结构与成分分析

Structural and component analysis of boron carbide films prepared by magnetron sputtering

近年来国际上^(3)He资源的短缺造成了基于^(3)He的中子探测器高昂的成本,而以碳化硼薄膜作为中子转换层的硼基中子探测器逐渐成为了最有前景的替代方案。通过直流磁控溅射制备了Ti/B_(4)C多层膜,并使用透射电子显微镜(TEM)、飞行时间二次离子质谱(ToF-SIMS)、X射线光电子能谱(XPS)等手段对薄膜的结构与成分进行表征。结果表明:Ti层存在结晶情况;H、O、N元素为薄膜内部的主要杂质,且多分布于Ti层与B_(4)C-on-Ti过渡层中;更高的本底真空度能够降低碳化硼薄膜内的杂质含量,提高B含量占比;中子探测效率测试结果证明本底真空度的提高能够有效提高碳化硼中子转换层的效率。

In recent years,the world’s shortage of ^(3)He resources has led to the high cost of ^(3)He neutron detectors.The boron-based neutron detectors using boron carbide films as neutron conversion layers have gradually become the most promising alternative.In this paper,we prepared Ti/B_(4)C multilayers using direct current magnetron sputtering method.The structure and composition of the films were characterized by transmission electron microscopy(TEM),time-offlight secondary ion mass spectrometry(ToF-SIMS),X-ray photoelectron spectroscopy(XPS).The results show that there is crystallization in the Ti layer.H,O,N are the main impurities in the films,and are mainly distributed in the Ti layer and B_(4)C-on-Ti transition layer.Higher base pressure can reduce the impurity content and increase the proportion of B content in the boron carbide films,thus improving the neutron conversion efficiency of the films.The results of neutron detection efficiency test prove that the high base pressure can effectively improve the efficiency of boron carbide neutron conversion layers.