外延生长亚单层Si薄膜的动力学蒙特卡罗模拟

Kinetic Monte Carlo Investigation of Submonolayer Homoepitaxial Growth on Si(100)

建立了沿Si(100)方向外延生长亚单层Si薄膜的动力学蒙特卡罗模拟模型,对二维Si薄膜的生长过程及二维Si岛的形貌演变进行了研究。结果表明,在一定的入射率下存在一最佳成岛温度,该温度随入射率的增大而升高。以最佳成岛温度生长时,岛密度随覆盖度的增加呈现增加—饱和—减小的变化规律。在低温和高入射率下,岛密度随覆盖度单调增加,薄膜呈离散生长。而温度很高和入射率很低时,岛密度始终以很小的数值在小范围内振荡,薄膜呈紧致生长。

The initial stages of Si（100） homoepitaxy are studied using Kinetic Monte Carlo（KMC） simulation. The results reveal that there is an optimum islanding temperature at a given deposition rate and this temperature increases with the increase of deposition rate. The islands density increases at first, then is saturate and decreases at last with the increase of coverage（0-0. 3） at the optimum islanding temperature. With coverage increasing, the island density increases continuously at low temperature and high deposition rate, otherwise it is always very low and fluctu- ates within a narrow range at high temperature and low deposition rate. The island morphology transits from dispersed shape to compact shape with increasing temperature or decreasing deposition rate.