样品温度对CF_3^+与Si表面相互作用影响的分子动力学模拟

Molecular dynamics simulation of temperature effects on CF_3^+ etching of Si surface

利用分子动力学模拟方法研究了不同温度下CFx层对CF3+刻蚀Si表面过程的影响.由模拟数据可知,温度对C和F的沉积有显著的影响;通过提高样品的温度,物理刻蚀得到了加强,而化学刻蚀被减弱.同时,随着温度的升高,Si的刻蚀率相应增加.刻蚀产物中的SiF,SiF2的量随温度的增加而增加,SiF3的量与基体温度没有直接的关系.Si刻蚀率的增加主要是通过提高SiF,SiF2从表面脱离的量得以实现的.通过比较发现CF3+在Si表面的沉积对后续的刻蚀过程产生了巨大的影响,具体表现为大大增加了Si的刻蚀率,减弱了Si的化学刻蚀机理。

Molecular dynamics method was employed to investigate the effects of the reaction layer formed near the surface region on CF3＋ etching of Si at different temperatures.The simulation results show that the coverages of F and C are sensitive to the surface temperature.With increasing temperature,the physical etching is enhanced,while the chemical etching is weakened.It is found that with increasing surface temperature,the etching rate of Si increases.As to the etching products,the yields of SiF and SiF2 increase with temperature,whereas the yield of SiF3 is not sensitive to the surface temperature.And the increase of the etching yield is mainly due to the increased desorption of SiF and SiF2.The comparison shows that the reactive layer plays an important part in the subsequeat impacting,which enhances the etching rate of Si and weakens the chemical etching intensity.