EVALUATION OF GAS PHASE REACTION RATE CONSTANT BY DEPOSITION PROFILE ANALYSIS FOR IN-SITU COUNTER DIFFUSION CVD

摘要

A modification of counter diffusion CVD, named in-situ counter diffusion CVD, using catalyst for producing reactant gas inside the reactor, is applied for estimating gas phase reaction between A1C13 and H2O in A12O3 CVD from A1C13/CO2/H2 reaction system. In counter diffusion CVD, two reactant gas diffuse from counter sides of the porous media to react and deposit narrow band of solid, and the width of deposition band depends on the rate of deposition process. Deposition experiment at 573 K on porous sintered stainless steel substrate with average pore size of 20μm - 100μm shows that the band width is independent to pore diameter. This indicates that the controlling step of the deposition process is the gas phase reaction and the width reflects some information on gas phase reaction rate. By simulation work assuming the 2nd order reaction the rate constant is estimated as 700 m~3 *mol~(-1) at 573 K.