Transport phenomena in an aluminum nitride induction heating sublimation growth system

In this paper, an integrated model considering induction heating, thermal system design, mass transport and growth kinetics has been developed to study temperature distribution in an aluminum nitride (AlN) growth system and evolution of the crystal interface and source surface. The electromagnetic field and induction heat generation are calculated by the Maxwell equations. Temperature distribution in the growth chamber is simulated by energy equation accounting for conduction/radiation. Simulation results are in good agreement with experimental measurements. Both of them show that temperature difference between the top and bottom of the crucible is almost independent of power. The effects of RF coil current on temperature distribution is investigated. The maximum temperature is located at about the center of the coils. Effects of pressure and temperature gradient on the growth rate are studied. The growth rate increases linearly with temperature gradient and decreases with pressure. Since the AlN source powder is porous, the effects of the powder porosity on the shapes of the crystal interface and source surface and the growth rate are also investigated.