Properties Of Titanium Nitride Films Research Articles

Properties of Titanium Nitride Films for Barrier Metal in Aluminum Ohmic Contact Systems

Properties of titanium nitride (TiN) films deposited by reactive sputtering and dc magnetron sputtering from composite target are studied. In the as-deposited films, a TiN (200) grain, which is the lowest energy grain and is dominant in bulk TiN, is grown in films from composite target. A resistivity of 44 µΩ-cm is attained. These results show that high quality TiN films can be deposited by dc magnetron sputtering employed TiN composite target. However, a TiN (111) grain is grown in TiN films by the nitridation of Ti. Nitridation of a reactively sputtered TiN film in ammonium is also studied. The TiN films deposited from composite target and formed by the nitridation of titanium show good barrier performance in Al-Si/TiN/Si Ohmic contact.

Optimizing optical properties of reactively sputtered titanium nitride films

New results on the optical properties of titanium nitride films are reported. Opaque and semitransmitting TiN films were prepared by d.c. sputtering from a titanium target in an Ar N 2 atmosphere. The sputtering system was deliberately overpumped to avoid hysteresis effects from target poisoning. It is demonstrated in detail that substrate heating during deposition significantly increases the IR reflectance and reduces the reflectance minimum in the visible region for opaque films. The heat mirror performance of semitransmitting, 10–20 nm thick films on glass is similarly improved. The improvement is attributed to reduction in lattice strain and oxygen and carbon impurity content as observed by X-ray diffraction and Auger electron spectroscopy. The results indicate that slightly overstoichiometric films exhibit better optical performance.

Evaluation of mechanical properties of TiN films by ultralow load indentation

The mechanical properties of titanium nitride films of varying composition deposited on stainless steel substrates were studied using an indentation technique with a mechanical properties microprobe which allows measurement of film properties without contribution from the substrate material. A polishing technique was developed that gave consistent indentation measurements on films with initially rough surfaces. The elastic modulus increases linearly with increasing nitrogen content in the N:Ti range of 0.5–1.05, while the hardness of the film depends on other factors. Possible factors contributing to the hardness of the films are discussed.

Titanium nitride deposited by dual ion beams

Titanium nitride films have been prepared by the dual ion beam (DIB) deposition technique, which consists of the ionized cluster beam (ICB) and the ionized gas beam (IGB). As the source of ICB, vaporized titanium is ejected through the multinozzle of the crucible into a high vacuum chamber and is cooled and clustered by adiabatic expansion. The titanium clusters thus obtained are partially ionized in an electron shower and accelerated to the substrate. At the same time, as the source of IGB, nitrogen molecules are partially ionized, excited and decomposed in an electron shower and also accelerated to the substrate. These two beams collide and combine together on their way to the substrate. The characteristics of the ion current density and the properties of titanium nitride films are investigated. It is found that the DIB technique has a great advantage in preparing titanium nitride films of various crystalline structures from TiN to Ti 2N at a low temperature with a high deposition rate over a large substrate. Therefore, the chemical reaction is enhanced by the irradiation of the ionized and excited gases and the migration of ionized clusters on the substrate.

Structure and Electrical Properties of Titanium Nitride Films

Metallic titanium, in nitrogen atmosphere with specified pressures (pN) ranging from 10-6 to 10-4 Torr, was evaporated on glass substrates heated at temperatures (Ts) between 300 to 500°C. X-ray analysis revealed that the films were composed of α-titanium, distorted titanium phase, amorphous phase, and TiN. The distorted titanium phase was found to extend to a high concentration of nitrogen (x=0.5). In particular, the specimens evaporated at pN=2.0×10-5 Torr and Ts=500°C had maximum resistivity of 270 µΩ-cm and a very small negative value of the temperature coefficient of resistance (0 to -20 ppm/°C) for an extended range of temperatures (-190 to 200°C). The excess resistivity of the distorted titanium phase can be mainly interpreted in terms of two kinds of carrier scattering, one due to nitrogen atoms randomly distributed at vacant interstitials, another attributable to grain boundaries involved.