动力学晶格蒙特卡洛方法模拟Cu薄膜生长

利用动力学晶格蒙特卡洛方法模拟了Cu薄膜在Cu(100)面上的三维生长过程。模型中考虑了四个动力学过程:原子沉积、增原子迁移、双原子迁移和台阶边缘原子迁移,各动力学过程发生的概率由多体势函数确定。讨论了基底温度、沉积速率及原子覆盖率对Cu原子迁移、成核和表面岛生长等微观生长机制的影响;获得了Cu薄膜的表面形貌图并计算了表面粗糙度。模拟结果表明,随基底温度升高或沉积速率下降,岛的平均尺寸增大,数目减少,形状更加规则。低温时,Cu薄膜表现为分形的离散生长,高温时,Cu原子迁移能力增强形成密集的岛。Cu薄膜表面粗糙度随着基底温度的升高而迅速减小;当基底温度低于某一临界温度时,表面粗糙度随原子覆盖率或沉积速率的增大而增大;当基底温度超过临界温度时,表面粗糙度随原子覆盖率或沉积速率的变化很小,基本趋于稳定。

Kinetic Lattice Monte Carlo Simulation of Cu Thin Film Growth

The Cu thin film growth process on Cu (100) metal substrate is investigated using a three-dimensional kinetic lattice Monte Carlo (KLMC) method. Four kinetic processes are included in our model: deposition, adatom diffusion, dimer diffusion and ledge adatom diffusion. The activation energies for these three diffusion events are calculated using the embedded-atom method. The dependence of the Cu thin film growth on process parameters, including substrate temperature, deposition rate and coverage, is discussed using the KLMC model. The results show that, as the substrate temperature increases or the deposition rate decreases, the average size of the islands becomes bigger and the number of the islands decreases. As the temperature is low, the film shows fractal growth; at higher temperature, the island becomes compact and more regular in shape. And the higher the temperature, the smaller the Cu thin film surface roughness. When the substrate temperature is lower than the transion temperature, the surface roughness increases as the deposition rate and (or) the coverage increases. At higher temperature, the surface roughness is almost the same for different deposition rates or the coverage.