摘要:
本文采用分子动力学模拟方法研究了F原子(能量在0.5—15eV之间)与表面温度为300K的SiC(100)表面的相互作用过程.考察了不同能量下稳定含F反应层的形成过程和沉积、刻蚀过程的关系以及稳定含F反应层对刻蚀的影响.揭示了低能F原子刻蚀SiC的微观动力学过程.模拟结果表明伴随着入射F原子在表面的沉积量达到饱和,SiC表面将形成一个稳定的含F反应层.在入射能量小于6eV时,反应层主要成分为SiF3,最表层为Si-F层.入射能量大于6eV时,反应层主要成分为SiF.但是由于最表层Si的刻蚀导致表层为C-F层.这个C-F层的形成将阻缓硅的进一步刻蚀.在入射能量小于6eV时,F极难对SiC进行刻蚀.在入射能量达到15eV时,开始出现C的刻蚀.刻蚀率随入射能量增加而增加,主要的刻蚀产物为SiF4,表明Si的刻蚀主要通过化学刻蚀方式.
关键词:
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分子动力学
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刻蚀
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能量
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SiC
Abstract:
In this study, molecular dynamics simulations are used to investigate atom F interacting with SiC at 300 K. Simulation results show that with the saturation of the deposition of F atoms on the surface, the compositions (SiFx and CFx groups (x4)) in the reaction layer reach a steady state. When incident energy is less than 6 eV, no etching is observed. With incident energy increasing, the etching yields of Si and C atoms increase. It is found that Si atoms are preferentially removed. For etching products, SiF4 is dominant. And the main etching mechanism of Si atoms is chemical etching.