The mass transport process in a showerhead MOCVD reactor is mathematically analyzed.The mathematical analysis shows that the vertical component velocity of a point over the substrate is only dependent on vertical dist...The mass transport process in a showerhead MOCVD reactor is mathematically analyzed.The mathematical analysis shows that the vertical component velocity of a point over the substrate is only dependent on vertical distance and is independent of radial distance.The boundary layer thickness in stagnation flow is independent of the radial position too.Due to the above features,the flow field suitable for film growth can be obtained.The ceiling height of the reactor has important effects on residence time and the mass transport process.The showerhead MOCVD reactor has a short residence time and diffusion plays an important role in axial transport,while both diffusion and convection are important in radial transport.展开更多
A systematic study has been performed to investigate the flow and thermal patterns of vertical rotating Thomas Swan MOCVD reactor at low pressure,using 2-D dynamic modeling.By varying and calculating the several impor...A systematic study has been performed to investigate the flow and thermal patterns of vertical rotating Thomas Swan MOCVD reactor at low pressure,using 2-D dynamic modeling.By varying and calculating the several important process parameters of the reactor,the optimized conditions of the uniform distributions of velocity and temperature profiles in steady state have been obtained.Then,time-dependent models with the step response perturbation of the total gas rate can help identify the visual transient behavior inside the reactor and analyze the mechanism of delay time,relaxation oscillation and pulsative oscillation.These results are beneficial to the process parameter optimization and geometrical configuration design of the MOCVD reactor.展开更多
A new three-layer hot-wall horizontal flow metal-organic chemical vapor deposition （MOCVD） reactor is proposed. When the susceptor is heated, the temperature of the wall over the susceptor also increases to the same...A new three-layer hot-wall horizontal flow metal-organic chemical vapor deposition （MOCVD） reactor is proposed. When the susceptor is heated, the temperature of the wall over the susceptor also increases to the same temperature. Furthermore, the flowing speed of the top layer is also increased by up to four times that of the bottom layer. Both methods effectively decrease the convection and make most of the metal organic （MO） gas and the reactive gas distribute at the bottom surface of the reactor. By selecting appropriate shapes, sizes, nozzles array, and heating area of the walls, the source gases are kept in a laminar flow state. Results of the numeric simulation indicate that the nitrogen is a good carrier to reduce the diffusion among the precursors before arriving at the substrate, which leads to the reduction ofpre-reaction. To get a good comparison with the conventional MOCVD horizontal reactor, the two-layer horizontal MOCVD reactor is also investigated. The results indicate that a two- layer reactor cannot control the gas flow effectively when its size and shape are the same as that of the three-layer reactor, so that the concentration distributions of the source gases in the susceptor surface are much more uniform in the new design than those in the conventional one.展开更多
文摘The mass transport process in a showerhead MOCVD reactor is mathematically analyzed.The mathematical analysis shows that the vertical component velocity of a point over the substrate is only dependent on vertical distance and is independent of radial distance.The boundary layer thickness in stagnation flow is independent of the radial position too.Due to the above features,the flow field suitable for film growth can be obtained.The ceiling height of the reactor has important effects on residence time and the mass transport process.The showerhead MOCVD reactor has a short residence time and diffusion plays an important role in axial transport,while both diffusion and convection are important in radial transport.
基金supported by the National Basic Research Program of China (Grant No.2003CB314901)National Natural Science Foundation of China (Grant Nos.10875018,10773002 and 60576018)+2 种基金National High Technology Research and Development Program of China (Grant Nos.2006AA03Z416 and 2007AA03Z418)111 Project (Grant No.B07005)Program for Changjiang Scholars and Innovative Research Team in University (Grant No.IRT0609)
文摘A systematic study has been performed to investigate the flow and thermal patterns of vertical rotating Thomas Swan MOCVD reactor at low pressure,using 2-D dynamic modeling.By varying and calculating the several important process parameters of the reactor,the optimized conditions of the uniform distributions of velocity and temperature profiles in steady state have been obtained.Then,time-dependent models with the step response perturbation of the total gas rate can help identify the visual transient behavior inside the reactor and analyze the mechanism of delay time,relaxation oscillation and pulsative oscillation.These results are beneficial to the process parameter optimization and geometrical configuration design of the MOCVD reactor.
基金supposed by the National Natural Science Foundation of China(Nos.60976008,61006004,61076001,10979507)the Special Funds for Major State Basic Research Project of China(No.A000091109-05)the High Technology R&D Program of China(No. 2011AA03A101)
文摘A new three-layer hot-wall horizontal flow metal-organic chemical vapor deposition （MOCVD） reactor is proposed. When the susceptor is heated, the temperature of the wall over the susceptor also increases to the same temperature. Furthermore, the flowing speed of the top layer is also increased by up to four times that of the bottom layer. Both methods effectively decrease the convection and make most of the metal organic （MO） gas and the reactive gas distribute at the bottom surface of the reactor. By selecting appropriate shapes, sizes, nozzles array, and heating area of the walls, the source gases are kept in a laminar flow state. Results of the numeric simulation indicate that the nitrogen is a good carrier to reduce the diffusion among the precursors before arriving at the substrate, which leads to the reduction ofpre-reaction. To get a good comparison with the conventional MOCVD horizontal reactor, the two-layer horizontal MOCVD reactor is also investigated. The results indicate that a two- layer reactor cannot control the gas flow effectively when its size and shape are the same as that of the three-layer reactor, so that the concentration distributions of the source gases in the susceptor surface are much more uniform in the new design than those in the conventional one.
