Reaction Analysis of Aluminum Chemical Vapor Deposition from Dimethyl-aluminum-hydride Using Tubular Reactor and Fourier-Transform Infrared Spectroscopy: Theoretical Process Optimization Procedure (1)

Abstract

Kinetic studies on the chemical vapor deposition (CVD) of aluminum from dimethylaluminumhydride (DMAH) were carried out to obtain the reaction model which is useful for the process optimization. Fourier-transform infrared spectroscopy (FT-IR) was used to monitor DMAH supplied to the reactor, which ensured the reliability of precursor delivery by the bubbling method. FT-IR was also used to identify the reaction product of DMAH. Aluminum deposition from DMAH yielded only trimethylaluminum (TMA). The analysis of aluminum deposition rate profile in the tubular reactor revealed that the rate-limiting step was the surface reaction of DMAH and that the surface reaction was almost of the first order with respect to DMAH concentration. The analysis took account of the monomer-dimer equilibrium of DMAH in the reactor whose existence was suggested by quantum-chemical calculations. The activation energy of approximately 80 kJ/mol was estimated from the relationship between DMAH decomposition yield and the gas residence time in the tubular reactor.