[17p-Z32-1~7] 15.1 Bulk crystal growth

▲ [17p-Z32-4] Simulation of the global thermal field in a setup for ammonothermal growth of GaN

〇(P)Saskia Carola Schimmel^1,2, Daisuke Tomida¹, Makoto Saito^3,4, Quanxi Bao^3,5, Toru Ishiguro³, Yoshio Honda¹, Shigefusa F. Chichibu^1,3, Hiroshi Amano¹ (1.IMaSS-Nagoya Univ., 2.Int. Research Fellow of JSPS, 3.IMRAM-Tohoku Univ., 4.Mitsubishi Chemical Corp., 5.Japan Steel Works)

Keywords:ammonothermal, GaN, numerical simulation

High-power and high-frequency devices are expected to benefit strongly from the availability of bulk GaN substrates grown by the ammonothermal method because of the achievable excellent structural quality and the scalability of the method. However, scale-up remains a time-consuming trial-and-error-based task due to the lack of knowledge on internal temperature distribution and flow field.
We examine the global thermal field inside an ammonothermal growth setup by a conjugated simulation of conductive, convective, and radiative heat transfer to evaluate how thermal boundary conditions should be defined in a detailed simulation of the autoclave and its interior. The results show that the temperature distribution inside the autoclave walls is not represented well by heater-long fixed temperatures at the autoclave wall. Thermal losses through an uninsulated autoclave head should not be neglected. Alternative methods for defining the thermal boundary conditions will also be discussed.