Thermal environment evolution and its impact on vapor deposition in large diameter AIN bulk growth

In an AIN sublimation growth system, to obtain a large and thick single crystal, it is very important to maintain the thermal environment suitable for growth inside the crucible during a long period of time (>100 Hours). In this paper, an integrated model capable of describing inductive, radiative and conductive heat transfer will be used to simulate the transient behavior of thermal environment inside the crucible during a 40-hour experiment growth. The effect of graphite insulation degradation on the temperature distribution inside the crucible will be investigated. Simulation results will be compared with the experiments data to study the effect of the insulation thermal conductivity and geometry change, the degradation induced particle deposition, and the crystal size enlargement on the temperature distribution achieved in the crucible and the growth rate. The relationship of graphite insulation degradation with power input change of the induction heated system will be established. The evolution of temperature difference between the surfaces of source material and crystal, which is the driving force of the growth, will be presented.