Design and Process Optimization of a New Reaction Cavity for High-Temperature MOCVD AlGaN Growth

AlGaN offers new opportunities for the development of the solid-state ultraviolet (UV) luminescence, detectors and high-power electronic devices, however, problems such as low growth rate and poor crystallization quality are common in the growing process of AlGaN material. In this paper, a new reaction cavity for high-temperature MOCVD AlGaN growth was carried out through the research of resistance heated, and the thermal field of high-temperature MOCVD growth was numerically simulated. Based on the high-temperature MOCVD reaction cavity, an orthogonal experimental method was used to simulate the process parameters, and the range, variance and matrix analysis were conducted on the calculation results. The finite element analysis was conducted on the temperature field, pressure field, velocity field, and the high-temperature MOCVD AlGaN growth model was established.

Ab initio study for molecular-scale adsorption, decomposition and desorption on AlN surfaces during MOCVD growth

Since AlGaN offers new opportunities for the development of the solid state ultraviolet (UV) luminescence, detectors and high-power electronic devices, the growth of AlN buffer substrate is concerned. However, the growth of AlN buffer substrate during MOCVD is regulated by an intricate interplay of gas-phase and surface reactions that are beyond the resolution of experimental techniques, especially the surface growth process. We used density-functional ab initio calculations to analyze the adsorption, decomposition and desorption of group-III and group-V sources on AlN surfaces during MOCVD growth in molecular-scale. For AlCH3 molecule the group-III source, the results indicate that AlCH3 is more easily adsorbed on AlN (0001) than (000$$\overline{1}$$ 1 ¯ ) surface on the top site. For the group-V source decomposition we found that NH2 molecule is the most favorable adsorption source and adsorbed on the top site. We investigated the adsorption of group-III source on the reconstructed AlN (0001) surface which demonstrates that NH2-rich condition has a repulsion effect to it. Furthermore, the desorption path of group-III and group-V radicals has been proposed. Our study explained the molecular-scale surface reaction mechanism of AlN during MOCVD and established the surface growth model on AlN (0001) surface.