Relationship between the process parameters and film properties of low temperature low pressure chemical vapor deposition titanium nitride films

Titanium nitride is deposited from the reactants TiCl sub(4) and NH sub(3), with Ar as a diluent gas. These depositions are carried out in a commercial cold wall single wafer reactor, equipped with a load lock and a HF cleaning module for the removal of native oxide. The influence of the TiCl sub(4) partial pressure on the TiN film properties and the growth rate is investigated. After an initial rise at low TiCl sub(4) partial pressure, the growth rate decreases with increasing TiCl sub(4) partial pressure. The decreasing deposition rate is caused by the presence of the complex forming reactions in the gas phase. During these depositions less than 5% TiCl sub(4) is consumed by the TiN deposition. However, high conversion fractions of the TiCl sub(4) ( > 15%) are observed during the initial rise of the deposition rate at low TiCl sub(4) partial pressures. A shift from the diffusion controlled region to the reaction controlled region seems to take place. This shift compares with a change in the film properties. The films deposited in the reaction controlled region are yellow gold colored. They all have the same film properties, i.e., a resistivity of 120 mu Omega multiplied by cm plus or minus 10 mu Omega multiplied by cm, chlorine concentration of 0.7 atom percent (a/o), contain no detectable amounts of oxygen and are preferential (200) orientated. The films deposited in the diffusion controlled region are dull reddish/brown and have higher values of the resistivity. These films show more randomly oriented grains and contain no detectable amounts of chlorine. However, in contrast with the former TiN films, these films contain about 5 a/o oxygen. The microstructure and the related surface roughness determine the visual appearance of these films.