KMC Study Of MOCVD Growth Of GaN Thin Film At Microscopic Level

Kinetic Monte Carlo algorithm has combined the Monte Carlo method and molecular dynamics theory. The algorithm has clear and simple structure, especially suit for simulation of the motion process of large particle s. The study of the growth process of Ga N film from a microscopic perspective has an important significance which because the surface morphology of the new film has a close relationship with the growth of island. So if we study the growth of film from the atomic level, it will be meaningful to develop the material process equipment and the growth environment. In this paper, the growth procedure of Ga N under MOCVD process has been simulated by the KMC method. So we can get the state of atoms on the surface o f Ga N film from a microcosmic perspective.Based on the experimental research, in this paper, the reaction path of Ga N material under MOCVD process has carried on the thorough research. According to the actual conditions, the models of gas and surface reaction have been given in this paper.Based on the CFD and the gas reaction model, the gas reaction process has been simulated with the Fluent software when the MMG is the main product of gas reaction. And the values of the concentration of the products which will become the reaction precursor of the surface reaction have been obtained at the same time.According to the above result of Fluent simulation, MC method and the model of surface reaction of Ga N film, the KMC model of Ga N materials under MOCVD process has been established. During the process of modeling, the 2D hexagonal shape substrate model has been build according to the structure of Ga N lattice. In order to avoid the boundary effect, the boundary of the substrate has been set to periodic.Based on the KMC model, we made a simulation of the growth condition of Ga N material. Under the condition of P=100torr and T=1000-1500 k, the situation of growth speed has been given under the different temperatures such as 1073 K, 1173 K, 1273 K, 1373 K, and 1473 K. And it has been found that the growth rate of Ga N material is not developing with the substrate temperature increasing. O n the contrary, it presents a process of rising at fist and falling at last. This phenomenon is consistent with the experimental results reported in literatures.The three-dimensional surface graph has been given under the condition of T=1273k, P=100torr. According to the simulation result, we found that the way of Ga N growth process can be approximate to 2D under the high thermal.By introducing a root mean square roughness equation, the situation of the film roughness has been simulated under the five temperature points mentioned above. And the quality of the thin film represented by the rsm value. The simulation result shows that the value of roughness(rsm) is decreasing with the improvement of temperature, which is consistent with the experimental results.