Thermodynamics Models for V-pit Nucleation and Growth in III-Nitride on Silicon
Thermodynamics Models for V-pit Nucleation and Growth in III-Nitride on Silicon
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DOI：
10.1007/s11837-020-04421-z
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发表时间：
2020-10
期刊：
影响因子：
2.6
通讯作者：
K. Khafagy;T. Hatem;S. Bedair
中科院分区：
文献类型：
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作者：
K. Khafagy;T. Hatem;S. Bedair
硅和蓝宝石是光伏和光嵌入二极管等多种应用中 AlN、InGaN 和 GaN 薄膜的常见基材。由于大的晶格和热膨胀系数 (TEC) 失配，在 III 族氮化物 (III-N) 层和这些衬底之间的界面处会产生穿透位错。 这些位错穿透 III-N 层的顶面，通过形成 V 坑缺陷来松弛系统。这项工作提出了一个基于热力学的模型，用于研究硅或蓝宝石衬底上的 InGaN/GaN 外延层中 V 坑的形成和生长。该模型通过 III-N 层中的应变能、形成新 V 坑的位错劣化能以及由于刻面形成而产生的 V 坑刻面能量之间的能量平衡来计算薄膜中 V 坑缺陷的演变。还研究了不同晶格和 TEC 失配以及一种新方法（嵌入空隙方法）对 V 坑成核和生长的影响。
Silicon and sapphire are common substrates for AlN, InGaN, and GaN thin films in several applications such as photovoltaic and light-embedded diodes. Threading dislocations are generated at interfaces between III-nitride (III-N) layers and these substrates because of large lattice and thermal expansion coefficient (TEC) mismatches. These dislocations penetrate the top surface of III-N layers to relax the system by forming V-pit defects. This work presents a thermodynamics-based model to study V-pit formation and growth in InGaN/GaN epilayers on either silicon or sapphire substrates. The model calculates the evolution of V-pit defects in thin films through the energy balance between the strain energy in the III-N layer, dislocation deterioration energy to form new V-pits, and V-pit facet energies that result because of facet formations. The impact of different lattice and TEC mismatches as well as a novel approach, the embedded void approach, on V-pit nucleation and growth is also investigated.