基于H-Si(100)表面上原子层沉积Al2O3的仿真研究

Simulation of Atomic Layer Deposition of Al_2O_3 on H-Si(100) Surface

通过对原子层沉积过程的计算机仿真,分析不同沉积条件对沉积过程的影响。以H-Si(100)表面原子层沉积Al2O3的过程为基础,通过分析基片上不同表面功能团之间的相互作用,将整个沉积过程分为初始沉积和后续生长两个阶段。基于不同的阶段建立相应的前驱体到达事件模型、反应事件模型以及表面解吸事件模型。采用动力学晶格蒙特卡罗方法实现这一沉积过程的仿真。实现了不同温度、不同真空条件下Al2O3的原子层沉积仿真。结果表明:在一定的范围内,前驱体或基片的温度高,反应室真空度低,薄膜生长速率的增长快,表面粗糙度小;基片温度对于薄膜沉积过程的影响最大,其阈值约为200℃。而且薄膜的生长趋势由初始的三维岛状生长向二维层状生长逐渐转变。

The atomic layer deposition （ALD） has been modeled and simulated in kinetic lattice Monte Carlo （KLMC） method to understand the influence of film growth conditions, including the substrate or the precursor temperatures and pressure,on the atomic layer deposition. The film growth of Al2O3 on H-Si（100） surface was taken as an example. The growth was divided into the initial deposition and linear growth stages, based on the reactions of the functional groups involved;and the precursor arrival, surface reaction and desorption were modeled respectively. The simulated results show that the substrate temperature and pressure strongly affect the deposition rate. For example, higher substrate temperature and lower the pressure result in a faster deposition rate and films with smoother surfaces. At a substrate temperatuire above 200℃, it affects the film deposition most strongly than other factors. In general, the film growth changes from 3-dimensional islands into 2 dimensional layers.