Kinetical Aspects of the LPCVD of Titanium Nitride from Titanium Tetrachloride and Ammonia

Abstract

Was deposited from the reactant gases , , and , with Ar as a carrier gas. The depositions were carried out in a cold wall CVD reactor at a total deposition pressure of 20.0 Pa (150 mtorr). The deposition rate and film properties were studied as a function of the deposition temperature and the partial pressure of the reactant gases. A rate equation for has been determined No influence of on the deposition rate and film composition was detected. Even without , deposition occurred in a gas mixture of , , and Ar. This suggests that does not play a role in the deposition reaction mechanism. The reaction order for and can only be explained qualitatively because of the existence of a deposition reaction and a parallel complex forming reaction in the gas phase. These two reactions take place simultaneously and competitively. The complex forming reactions in the gas phase influence the reactant partial pressures. Until now this influence has not been known quantitatively. Therefore, a detailed reaction mechanism of the deposition could not be extracted from our results. An activation energy of 61 kJ/mol has been determined. At increasing deposition temperature and at higher values of the ratio, lower values of electrical resistivity were observed. This resistivity variation is found to be caused by the impurity content (Cl and O) in the films, which varies with the process parameters.