扩散
无定形固体
氢
空位缺陷
氧气
动力学蒙特卡罗方法
材料科学
活化能
分析化学(期刊)
化学
标识
DOI:10.1016/j.commatsci.2021.111109
摘要
• Oxygen vacancy (V O ) defect is an essential origin of bias stability in oxide TFT devices. • Common measurement methods are not sufficient to accurately quantify Vo concentration ( n Vo ) in amorphous In-Ga-Zn-O (a-IGZO). • V O tends to capture H atoms to increase their migration energy barriers. • Simulated hydrogen diffusion in a-IGZO is used to evaluate n Vo . A multiscale approach is presented to calculate the hydrogen diffusion in amorphous In-Ga-Zn-O (a-IGZO). Based on the fact that the presence of oxygen vacancy (V O ) defects suppresses the hydrogen diffusion in a-IGZO, the simulated H diffusion depth is utilized to evaluate the V O concentration ( n Vo ). The kinetic Monte Carlo (kMC) simulation is carried out to obtain the depth profiles of H diffusion in a-IGZO, which uses input of the H migration energy barriers ( E A ) calculated within the density functional theory (DFT) method. The DFT calculations showed that when H occupies the V O defects, its E A becomes higher than that of the interstitial H, which eventually suppresses H diffusion. The H diffusion function depending on n Vo and temperature, f D ( n Vo , T ), is readily obtained fitting the complementary error function to the simulated H diffusion profile. It is observed that f D ( n Vo , T ) can closely reproduce the experimentally measured H diffusion from literature with n Vo being comparable to the measured carrier concentration that can be speculated as the upper limit of n Vo . The properties of H diffusion in a-IGZO are examined in detail to address the application of the presented approach for estimation of n Vo.
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