The group Ⅲ nitrides are an important class of materials with aplications in UV and visible optoelectronics,high temperature electronics,cold cathodes and solar blind detectors.In recent years,with the realisation of...The group Ⅲ nitrides are an important class of materials with aplications in UV and visible optoelectronics,high temperature electronics,cold cathodes and solar blind detectors.In recent years,with the realisation of nitride based LEDs,the use of GaN IED has the potential to compete with 1raditional filament and discharge lamps,for the provision of white lighting,and there has been an explosion of interest in the MOCVD growth of GaN based materials with an increasing focus on large area multiwafer reactors and wafer uniforrmity.This paper will review the design philosophy and characteristics of close-coupled showerhead reactors,relating these to the requirements of group Ⅲ-nitride growth,and will present a selection of data resulting from the operation of such equipment.These results suggest that the close coupled showerhead style of reactor is very suitable for the growth of GaN based structures in both research and production environments.展开更多
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
文摘The group Ⅲ nitrides are an important class of materials with aplications in UV and visible optoelectronics,high temperature electronics,cold cathodes and solar blind detectors.In recent years,with the realisation of nitride based LEDs,the use of GaN IED has the potential to compete with 1raditional filament and discharge lamps,for the provision of white lighting,and there has been an explosion of interest in the MOCVD growth of GaN based materials with an increasing focus on large area multiwafer reactors and wafer uniforrmity.This paper will review the design philosophy and characteristics of close-coupled showerhead reactors,relating these to the requirements of group Ⅲ-nitride growth,and will present a selection of data resulting from the operation of such equipment.These results suggest that the close coupled showerhead style of reactor is very suitable for the growth of GaN based structures in both research and production environments.
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.
