normalTiN was deposited from the reactant gases TiCl4 , NH3 , and H2 , 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 normalTiN has been determined r=1.3×10−5exp)(−7500/T·PH20·PNH31.3·PTiCl4−0.5 No influence of H2 on the deposition rate and film composition was detected. Even without H2 , deposition occurred in a gas mixture of TiCl4 , NH3 , and Ar. This suggests that H2 does not play a role in the normalTiN deposition reaction mechanism. The reaction order for NH3 and TiCl4 can only be explained qualitatively because of the existence of a normalTiN 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 normalTiN 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 PNH3/PTiCl4 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 normalTiN films, which varies with the process parameters.

Titanium nitride is deposited from the reactants TIC14 and NH3, 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 TIC14 partial pressure on the TiN film properties and the growth rate is investigated. After an initial rise at low TIC14 partial pressure, the growth rate decreases with increasing TIC14 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 % TiCl4 is consumed by the TiN deposition. However, high conversion fractions of the TiCl4 (> 15 %) are observed during the initial rise of the deposition rate at low TIC14 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 ~If~ 9 cm • i0 ~If~ 9 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.TiN coatings are widely used in several technological applications due to their hardness, gold color, high melting point, good thermal and electrical conductivity, and corrosion resistance. '-4 TiN films as diffusion barriers are an important application in the IC industry. 24 Conventionally, these TiN films are deposited by reactive sputtering 4 or by nitriding of sputtered titanium layers. 5 However, as IC feature sizes shrink to sub-micron dimensions, the ability of physical techniques, such as sputtering, to coat uniformly high aspect ratio vias has become a concern. Replacing the physical technique by chemical vapor deposition (CVD) is an alternative to circumvent this problem. Deposition of low pressure CVD (LPCVD) TiN with conformal step coverage is possible with TiCl4 and NH3 as reactants. ~'7 It has already been shown that in a contact hole with aspect ratio of 1.9 a step coverage of 100% can be achieved. ~ However, TiN films deposited with these reactants contain more than 2 atom percent (a/o) chlorine at deposition temperatures below 550~A disadvantage of the chlorine contamination is the corrosive nature of this element, e.g., in combination with aluminum, which might shorten the life time of an IC. An increasing amount of chlorine gives also a higher film resistivity. 8 Other TiN film properties, influencing the resistivity are the oxygen contaminatio...

Auger electron spectroscopy, x-ray photoelectron spectroscopy, and secondary-ion mass spectrometry have been used to elucidate the role of surface segregation and preferential sputtering of bismuth in rf-magnetron-sputtered bismuth–iron-garnet films. It turns out that bismuth is enriched by a factor of up to 2.4, as compared to the bulk content, within the first 1–1.5 nm beneath the advancing film surface during growth. Furthermore, Ar+-ion bombardment at projectile energies as low as 50 eV gives rise to a rather complete depletion of bismuth in the garnet surface. As neither surface segregation nor preferential sputtering of bismuth can be observed in as-polished single-crystalline Bi12SiO20 used as our reference, we conclude that the bond strength between bismuth and oxygen is weaker than that of the other garnet constituents. This is confirmed by comparing the calculated sputter yield of the element oxide. Thus, bismuth-rich crystallographically perfect epitaxial iron-garnet films can only be grown by sputtering if the growing film is protected against energetic particle bombardment.