The Numerical Simulation Of GaN Growth By Hydride Vapor Phase Epitaxy

With the rapid development of initial blue and ultraviolet photoelectric devices, the demand of the third generation of semiconductor materials has soared in the market. As a representative of the third generation of semiconductor, gallium nitride（GaN） is most widely used. In order to fundamentally across GaN devices the quality and efficiency of bottleneck, technology of providing GaN substrate preparation is becoming more and more attention. The hydride vapor phase epitaxy（HVPE） method is regarded as the most feasible GaN substrate means growth. This paper is in view of the growth of 4 inch GaN substrate of large size horizontal HVPE systems, growth process is simulated in omputational fluid dynamics（CFD） simulation method.This paper Is optimized in the traditional HVPE system, between the GaCl and NH₃ tube to add a way, it can stop the GaCl and NH₃ to react in advance, and at the same time can effectively control the uniformity of GaN extension. At the same time, as the factors affect the growth of GaN,two-dimensional and three-dimensional simulation is carried out.In a two dimensional model, we first studied the V/III ratio on the growth. The results of simulation show that, when the GaCl proportion is 0.06（the V/III ratio of 27）, the growth rate of GaN is best on the substrate. From the influence of splitter on the growth of GaN, optimization of the splitter can be conductive to GaN growth of the middle 80% area of the substrate. Growth of GaN on both ends of the substrate can be optimized through the outer layer of N2. In addition, by further change of Angle optimization of substrate reaction cavity, the uniformity of the GaN epitaxial film eventually reached 0.7%.In view of the non axisymmetric horizontal reaction cavity, this article also has carried on the three-dimensional modeling and simulation. This make the results more close to actual system. In V/III ratio optimization experiments, we found that if we use two-dimensional conclusion, NH₃ is obviously excessive. If we further improve the concentration of the GaCl, when the GaCl proportion is 0.17（the V/III ratio is10）, the optimal growth uniformity is best. Also, we found that the requirements of the separating gas flow rate increasese in the three-dimensional model. the optimal velocity is 0.11 m/s, it is 5.5 times that of the two-dimensional results. These results provides theory basis for parameter optimization of growth process, and it has certain guiding significance of reality.