Raman spectroscopy and flow visualization studies of MOVPE reactors

• Published in: Journal of crystal growth 1988, Vol.93 (1-4), p.270-278
• Main Authors: Monteil, Y., Favre, R., Bekkaoui, A., Raffin, P., Bouix, J., Marcillat, J., Dutto, P.
• Format: Article
• Language: English
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/0022-0248(88)90539-8

Raman spectroscopy, gas flow laser visualization and laser velocimetry have been simultaneously used to determine the thermodynamical characteristics of the gas flow in several MOVPE reactors. Raman spectroscopy has proved to be an useful tool to establish the temperature distribution from the rotation modes of H2 or N2. Small particles produced either by ultrasonic nebulizor or Dräger reagent tube transported in a stream of H2 or N2 were used for laser visualization and laser Doppler velocimetry/(LDV) methods. First, we noticed a different behaviour between H2 and N2. Using H2 as carrier gas in vertical reactor, a jet which extended from the coaxial pipe inlet to the susceptor and also large recirculation vortex were observed. For each vertical reactor we noticed a critical flow that corresponds to a change of dynamic flow pattern. The use of the Gr·Re−2 parameter gave a simple explanation for this change. The influence of the rotation of susceptor on the radial temperature distribution above the 2 inch susceptor has been studied