CFD modelling of HVPE reactor for gallium nitride deposition
Multi-scale and/or multi-disciplinary approach to process-product innovation
CFD & Chemical Engineering- I (T3-4a)
Keywords: HVPE, CFD modelling, gallium nitride, V/III semiconductors
CFD modelling of HVPE reactor for gallium nitride deposition
Lukasz Sytniewski 1, Alexei Lapkin 1, Wang N. Wang 2
1 Catalysis and Reaction Engineering Group, Department of Chemical Engineering, University of Bath, Bath BA2 7AY, UK
2 Department of Physics, University of Bath, Bath BA2 7AY, UK
Gallium nitride (GaN) is an excellent candidate for high temperature and high power optoelectronic devices such as blue-violet light emitting diodes (LED’s) or lasers, with a major application in high-density DVD data storage technology. However, in the heteroepitaxy process, the most common technique for the growth of freestanding GaN, the dislocation density is still a critical issue which limits the lifetime of devices and availability of low-cost high quality materials for mass market. The homoepitaxy growth process can reduce the defects dislocation density by two or even three orders of magnitude. Only the hydride vapor phase epitaxy process (HVPE) seems to be a suitable and economically justified technique to grow thick freestanding gallium nitride crystals on hetero-substrates, which can then be used in the homoepitaxy process. To reduce the overall cost of experimental procedure and facilitate process development, computational fluid dynamics has been used in the project to optimize the reactor design affecting required species concentration on the substrate, the correct N:Ga species ratio and optimal flow conditions.
In this work the design and modeling of vertical up-flow (substrate located faced down in the top part of reactor) HVPE reactor for growth of a single 2-inch wafer of gallium nitride using ANSYS CFD will be presented. The full fluid flow simulation, with the radiation and buoyancy model included, showing species concentration, V/III ratio and growth rate calculations (assuming 100 % conversion of gallium chloride into gallium nitride on the substrate) at different flows conditions, pressures and reactor chamber configurations will be presented. The predictions of parasitic nucleation on the reactor chamber walls will be reported. The model is being extended to simulate gas phase and surface chemical reactions. Comparison of the results generated by ANSYS CFD with the results obtained by FLUENT CFD for one of the reactor chamber shapes at the same flow conditions will be shown as well.
Keywords: HVPE, CFD modelling, gallium nitride, V/III semiconductors
Presented Tuesday 18, 12:00 to 12:20, in session CFD & Chemical Engineering- I (T3-4a).
