蒙特卡罗法单晶硅的腐蚀工艺表面微观形态仿真研究

Monte Carlo Simulation for the Surface Morphology of Anisotropic Etching of Crystalline Silicon

讨论了基于蒙特卡罗法模拟各向异性腐蚀加工的微观表面形态的仿真方法.应用台阶流动模型,分析了(h,k,l)晶面中(h+2,h,h),(h,1,1),(h+2,h+2,h)以及(h,h,1)晶面族上反应活跃的台阶部位原子的排列特征,结合微掩模的作用和定义方法,提出了通过限制各晶面族台阶部位广泛存在的一级、二级邻居数为(3,7)原子移除概率的方法来模拟快速反应区域的吸附抑制现象.把上述内容应用于RPF函数对(100)面的凸起结构,(110)面的带状条纹以及(111)面的三角形凹陷微观结构进行了仿真计算,解释了腐蚀中微观形貌的特征和成因.算法在3种基础晶面和高指数(322)晶面的计算结果能够很好地符合实验中观察到的表面形态微观特征,验证了方法的有效性.

This paper presents a Monte Carlo method for the simulation of the surface morphology during wet anisotropic etching. Based on the step flow model, the atomistic characteristics of the active step region of four silicon crystalline families （ h ＋ 2, h, h）, （ h, 1,1）, （ h ＋ 2, h ＋ 2, h ）, and （ h, h, 1 ） are investigated. Atoms with 3 first neighbors and 7 second neighbors on the active step re- gion are restricted in the removal probability under the effect of both micro mask and silicate particles adherence. By applying the above conditions on the RPF function, the formation of pyramid protrusion on （100） plane, the zigzag strip structures on （110） plane,and triangular etch pits on （111） plane is explained and simulated. The simulation result on three principle planes and high index （332） plane agrees well with the surface morphology from the experiment, which provides verification of the simulation method.