低能Cl原子刻蚀Si(100)表面的分子动力学模拟

使用分子动力学模拟方法研究了不同能量(0.3—10 eV)的Cl原子对表面温度为300 K的Si(100)表面的刻蚀过程.模拟中采用了Tersoff-Brenner势能函数来描述Cl-Si体系的相互作用.模拟结果显示,随着入射Cl原子在表面的吸附达到饱和,Si表面形成一层富Cl反应层.这和实验结果是一致的.反应层厚度随入射能量增加而增加.反应层中主要化合物类型为SiCl,且主要分布于反应层底部.模拟结果发现随初始入射能量的增加,Si的刻蚀率增大.在入射能量为0.3,1和5 eV时,主要的Si刻蚀产物为Si 关键词： 分子动力学 Cl刻蚀Si 分子动力学模拟 微电子机械系统

Molecular dynamics simulations of low-energy Cl atoms etching Si(100) surface

In this study, molecular dynamics simulation method is used to investigate the interactions of Cl continuously bombarding a crystalline Si (100) surface in an incident energy range of 0.3—10 eV.The surface temperature is set to be 300 K for all the incident energies. The improved Tersoff-Brenner type potential is employed.The simulation results show that a Cl-rich reaction layer is formed on the surface due to Cl continuously bombarding. The SiCl group is the predominant species in the reaction layer.The thickness of the reaction layer increases with incident energy. The etching ratio increases with incident energy increasing. The main etching product is SiCl₄ when the incident energies are 0.3, 1 and 5 eV, but it is SiCl_x(x<4) when the incident enery is 10 eV.With the incident energy increasing, the main etching mechanism changes from chemical etching to physical etching.