GAS-PHASE KINETICS FOR TIO2 CVD - HOT-WALL REACTOR RESULTS

We have studied the growth kinetics of TiO2 chemical vapor deposition using the decomposition of Ti(i-OC3H7)(4) (TTIP, titanium tetra-isopropoxide) in a hot-wall, axial flow low-pressure chemical vapor deposition reactor. Under conditions of high reactant conversion, we obtain polycrystalline, fully dense anatase TiO2 films at growth rates up to 0.2 mu m h(-1). The kinetic results (i.e., measured growth rates and axial film-thickness profiles) are analyzed using a two-dimensional reactor transport model and the gas-phase reaction mechanism that we proposed previously. This analysis yields a value for the rate constant of the gas-phase activation step (k(1) [cm(3) mole(-1) s(-1)] = 4.0 x 10(11) exp(-40[kJ mole(-1)]/RT) that is consistent with the value obtained from our earlier kinetic experiments performed using a cold-wall, impinging how reactor. In particular, the present results confirm the seemingly low value for the activation energy of the proposed gas-phase activation step obtained in our earlier work.