Point defect reduction in MOCVD (Al)GaN by chemical potential control and a comprehensive model of C incorporation in GaN
Point defect reduction in MOCVD (Al)GaN by chemical potential control and a comprehensive model of C incorporation in GaN
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DOI：
10.1063/1.5002682
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发表时间：
2017-12-28
影响因子：
3.2
通讯作者：
Sitar, Zlatko
中科院分区：
文献类型：
--
作者：
Reddy, Pramod;Washiyama, Shun;Sitar, Zlatko
提出了点缺陷形成能与生长过程参数之间的定量关系的理论框架。在金属有机化学气相沉积(MOCVD)的III-氮化物中，它能够通过控制化学势来系统地减少点缺陷。以C掺入GaN为例进行了实验验证。该理论模型成功地定量预测了GaN中C-N缺陷随生长参数的变化，并对晶界相和其他杂质化学反应提供了有价值的见解。金属过饱和度被发现是决定III/N化学势的主要因素，从而决定了涉及III或N原子与储存库交换的点缺陷的并入或形成。该框架具有通用性，可推广到(Al)GaN中的其他缺陷系统。证实了密度泛函理论中常用的平衡形式在预测非平衡高温MOCVD生长中缺陷掺入的有效性。此外，所提出的理论框架可以用来确定在任何给定的约束条件下实现最小补偿的最佳生长条件，例如生长速率、晶体质量和其他实际系统限制。由AIP出版公司出版。
A theoretical framework that provides a quantitative relationship between point defect formation energies and growth process parameters is presented. It enables systematic point defect reduction by chemical potential control in metalorganic chemical vapor deposition (MOCVD) of III-nitrides. Experimental corroboration is provided by a case study of C incorporation in GaN. The theoretical model is shown to be successful in providing quantitative predictions of C-N defect incorporation in GaN as a function of growth parameters and provides valuable insights into boundary phases and other impurity chemical reactions. The metal supersaturation is found to be the primary factor in determining the chemical potential of III/N and consequently incorporation or formation of point defects which involves exchange of III or N atoms with the reservoir. The framework is general and may be extended to other defect systems in (Al)GaN. The utility of equilibrium formalism typically employed in density functional theory in predicting defect incorporation in non-equilibrium and high temperature MOCVD growth is confirmed. Furthermore, the proposed theoretical framework may be used to determine optimal growth conditions to achieve minimum compensation within any given constraints such as growth rate, crystal quality, and other practical system limitations. Published by AIP Publishing.