Mullins’ theory predicts the buildup of adatoms during surface diffusion at the edges of grooves where grain boundaries emerge to the surface of a polycrystalline film. However, the mesoscopic nature of this theory prevents the identification of the atomic-scale physical mechanisms involved in this phenomenon. Here, we interpret the buildup of adatoms in atomistic terms through a mean-field rate-equation model and demonstrate both its kinetic nature and its impact on the intrinsic stress in these systems. Furthermore, the model provides estimates of the surface profile of intrinsic stress, of its typical mean values, and of the dependence of stress on temperature and deposition flux for different growth stages. These estimates agree well with reported experimental results obtained from recent advances in nanoscale mapping of mechanical stresses on the surface of polycrystalline films.

穆林斯的理论预测，在表面扩散期间，在晶界出现在多晶膜表面的沟槽边缘处，会形成原子。但是，该理论的介观性质阻止了对此现象涉及的原子级物理机制的识别。在这里，我们通过平均场速率方程模型以原子性方式解释了原子的积累，并展示了其动力学性质及其对这些系统内在应力的影响。此外，该模型还提供了固有应力的表面轮廓，其典型平均值以及不同生长阶段应力对温度和沉积通量的依赖性的估计。