Simulation Of Reactor Of MOCVD System Used For Manufacture Of GaN Material

GaN, one of the third generation of semiconductor, becomes the hot point of research because of its excellent characteristics. It has wide potential application and development in the fields of microelectronics and optoelectronics. However, now the internal fabrication technique of MOCVD reactor for the growth of GaN,gets behind with advanced level in world. The reactor manufacture is only carried out in some research units for the use of laboratory research, with fewer research works for the reactor designment and optimization being took out. Therefore, it is necessary to study the growth rules of GaN material in different shapes of MOCVD reactor.In the dissertation, by using the software of PROCOM, Gas concentration and temperature distribution in the horizontal MOCVD reactor are simulated,so is in the vertical MOCVD reactor. At the same time, some growth parameters are studied, which affect the growth surroundings, growth rate and uniformity of GaN material. The main works are as follows:Firstly, model for the horizontal MOCVD reactor was set up. The model of chemical reaction in the air of reactor and surface deposited reaction equations were also established successfully. Under the ideal condition, the effect of growth parameters such as the flux of NH3, the flux of TMGa andⅤ/Ⅲratio on the growth velocity of GaN material is studied. It is found that the growth velocity of GaN does depend on the flux of TMGa, growth temperature and the flux of N2 reversely, but not on theⅤ/Ⅲratio and gas pressure in the reactor directly. The growth velocity of GaN increases with an increase in the flux of TMGa. The best scope of growth temperature should lie between 900 and 1050℃. According to the growth conditions, the substrate that tilts to one side reasonably can improve the thickness uniformity.Secondly, model for the vertical MOCVD reactor of XiDian University was set up. On the foundation of the model, the flow field, temperature field and growth rate velocity distribution can be simulated. It is found that, the temperature field grads on the edge of substrate are higher, and the gas concentration increases rapidly with the horizontal distance increasing from the center of the substrate. The growth velocity of GaN on the center of substrate is the lowest, while is the highest on edge; the distribution of temperature above the substrate is suppressed with an increasement in the flux of N2, and it is useful to decrease the chance of reaction beforehand when isotherm in the reactor approaches the edge of substrate.Lastly by analyzing the changes of the radius of substrate and quartz tube, it shows...