Modeling on ammonothermal growth of GaN semiconductor crystals
- 作者：Qi-Sheng Chen ; qschen@imech.ac.cn ; [Author Vitae] ; Jun-Yi Yan ; [Author Vitae] ; Yan-Ni Jiang ; [Author Vitae] ; Wei Li ; [Author Vitae]
- 关键词：GaN crystal ; Baffle opening ; Ammonothermal growth ; Mass transfer
- 刊名：Progress in Crystal Growth and Characterization of Materials
- 出版年：2012
- 期刊代码：88_09608974
- 类别：ch
- 出版时间：June-September, 2012
- 卷：58
- 期：2-3
- 页码：61-73
- 文件大小：968 K
摘要
Ammonothermal systems are modeled using fluid dynamics and heat and mass transfer models. The nutrient is considered as a porous media bed and the flow is simulated using the Darcy-Brinkman-Forchheimer model. The resulting governing equations are solved using the finite volume method. The effects of baffle design on flow pattern, heat and mass transfer in an autoclave are analyzed. For the research-grade autoclave with an internal diameter of 2.22聽cm, the constraint for the GaN growth is found to be the growth kinetics and the total area of seed surfaces in the case of baffle opening of 10%(including the central opening of 5%and ring opening of 5%). The fluid flow across the baffle is a clockwise circulating flow which goes upwards in the central hole and downwards in the ring gap. Transport phenomena have been also studied in large-size ammonothermal growth systems with internal diameters of 4.44聽cm and 10聽cm. The flow pattern across the baffle changes to an anticlockwise circulating flow which goes upwards in the ring gap and downwards in the central hole in the case of 10%baffle opening. Since ammonothermal growth experiments are expensive and time-consuming, modeling becomes an effective tool for research and optimization of the ammonothermal growth processes.