HfO2和Al2O3混合原子层沉积反应机理的密度泛函理论研究

密度泛函理论研究了用HfCl4和Al(CH3)3作为前体,HfO2和Al2O3在硅表面的原子层沉积的机理,其包括2个沉积半反应:(1)HfCl4和Al—OH*的表面反应;(2)Al(CH3)3和Hf—OH*的表面反应。计算结果表明,2个半反应过程机理相似,内禀反应坐标研究也表明2个半反应经历了相似的过渡态和副产物的消除路径。另外,升高反应温度,反应(1)中间体的解吸附作用增强,而活化能降低,反应(2)活化能基本不变。

Surface reaction mechanisms of HfO2-Al2O3alloy grown on silicon by atomic layer deposition:A density functional theory study

Density functional theory(DFT) is employed to investigate atomic layer deposition(ALD) mechanism of hafnium oxide(HfO2) and alumina(Al2O3) on silicon surface.The ALD process using HfCl4 and Al(CH3)3 as precursors in this study involves two alternate deposited half-reaction: 1) HfCl4 with Al—OH surface sites,and 2) Al(CH3)3 with Hf—OH surface sites.Both half-reaction proceed through an analogous trapping-mediated mechanism.The intrinsic reaction coordinate studies also show both of them proceed the same transition state and reaction path of HCl elimination regardless of the surface cluster size.In addition,if the surface temperature is raised,the desorption of intermediates in reaction 1) will be enhanced while the activation energy will be decreased,and the activation energy of reaction 2) will be basically unchanged.