Abstract
The kinetics of the CVD of boron nitride from trimethoxyborane (TMOB) and ammonia (NH~3~) under atmospheric pressure was investigated by varying the following process parameters: temperature, residence time of the reactants, molar fraction of TMOB, and the NH~3~/TMOB ratio, Ξ³. A kinetic power law equation was derived, that describes the experimental results with good accuracy. The reaction order with respect to TMOB is found to be 0.9 and ββ0.2 with respect to NH~3~. Between 800βΒ°C and 950βΒ°C, the deposition rate is controlled by the surface reaction kinetics with apparent activation energy of 115.1βkJβmol^β1^. The deposited BN films were characterized by IR spectroscopy, Raman spectroscopy, and Xβray diffraction (XRD). The microstructure of the deposits depends on the nature of the substrates used. Turbostratic boron nitride (tβBN) was deposited on graphite, and hexagonal boron nitride (hβBN) on alumina substrates. Xβray photoelectron spectroscopy (XPS) analyses show nearly stoichiometric BN films for deposition temperatures in the range 850β950βΒ°C for high amounts of ammonia (100β<βΞ³β<β150) in the feed gas.