Stress In TiN Films Research Articles

Residual Stress Evolution by the ex-situ Annealing of TiN Thin Films Deposited on Steel Substrates

TiN thin films were deposited on high speed steel substrates by a PVD method at substrate temperatures of 450 °C (film A) and 200 °C (film B). Structural properties of the films were studied by X-Ray diffraction and atomic force microscopy. Residual stresses in the films are determined by a X-Ray diffraction method. It is found that film A has an average residual stress of about 8 GPa and a rougher surface. Film B has a smoother surface and a larger residual stress (12 GPa). By annealing at a temperature of 450 °C for four hours, the residual stress in film B is reduced to the same level as that in film A. The mechanisms which affect the residual stress of TiN films will be discussed.

Effect of substrate bias voltage on the properties of arc ion-plated TiN films onto high speed steels

The effect of substrate bias voltage on the properties of arc ion-plated TiN films onto high speed steels has been investigated. The high density structure with a large crystallite size grew at the high bias voltage. TiN films deposited by higher bias exhibited strong preferential (111) orientation from XRD. The internal stress of TiN films increased at first with increasing substrate bias voltage; however, it decreased as the bias voltage increased over 100 V. The coating adhesion measured by the scratch tester increased with increasing bias voltage, and this is coupled with a cohesion of films. Cutting performance of TiN coated drills, which increased markedly with increasing substrate bias, has been studied in relation to the physical and chemical properties of deposited films.

ＴｉＮ被覆材の残留応力の成膜温度および膜厚依存性

Large residual stress is formed in the coating of ceramic material deposited on a metal substrate because of difference in thermal expansion coefficient between the film and the substrate and of some other reasons. The residual stress greatly influences the mechanical properties of the film and the coated material. Therefore, the residual stress is one of the most important factors on evaluating the strength of coated materials.In the present investigation, we studied the residual stress in TiN film deposited on a substrate of spring steel by a multi-arc method as a function of depositing temperature and film thickness. The residual stress in the substrate layer near the interface was also investigated.The TiN film exhibited highly {111}-orientation, i.e., [111] of TiN crystals orients parallel to the surface normal of the substrate within ±10 degrees. The residual stress in the TiN film could be evaluated by the two-exposure method with getting the lattice strains for 222 diffraction at φ=0° and 70.5° determined by the relation of crystallographic orientation. The results revealed the compressive residual stress of -5.5--3.5GPa which is very large compared with the thermal residual stress due to the thermal strain mismatch between the film and the substrate. The residual stress value was greatly depended on the depositing temperature; it decreased with increasing temperature, and thickness of TiN film and increased with increasing film thickness. The residual stress in the substrate was compressive and below -30MPa probably due to the implantation of Ti ions into a shallow layer of the substrate.

Stress behavior of TIN films formed by reactive ion-beam-assisted deposition

The effect of ion species and ion energy on the intrinsic stress in TiN films formed by reactive ion-beam-assisted deposition has been examined. The result shows that the stress changes from tensile to compressive and increases in magnitude with increasing ionic mass and ion energy. This stress annealing is considered to be momentum controlled.

On the adhesion of plasma-deposited TiN on M2 steel

The adhesion of plasma-deposited TiN from TiCl 4H 2N 2 gas mixtures on AISI M2 (Werkstoffnr. 1.3343) steel substrates can be improved by proper cleaning of the substrates in a non-corrosive solution such as an aliphatic hydrocarbon (dodecane). From the deposition parameters, such as the substrate temperature, pressure, r.f. power and respective gas flows, the temperature appears to be the most influential parameter for the adhesion. The removal or reduction of metal oxides present on the surface by increasing the substrate temperature and/or in situ plasma etching in H 2 enhances the adhesion, as indicated by the increased critical load L c in a scratch adhesion test. The “cleaned” surface can be made more resistant to the aggressive discharge by treating the surface in an N 2 or N 2H 2 discharge. The nitrides formed on the surface, one of which is Fe 2N, also influence the nucleation and growth mechanism of TiN, which leads to a more random orientation of the TiN crystallites. The residual stress in TiN films, deposited on M2 steel substrates pre-treated in an N 2 discharge, appears to be lower than the stress in TiN films deposited on a steel surface which has not been pre-treated in an N 2 discharge. As a result a substantial improvement is obtained in critical load. Routine L c values of up to 50 N have been obtained for TiN coatings with a thickness of about 4.5 μm.

7159. A further study of the state of residual stress in TiN films made by physical vapor deposition methods: AJ Perry, J Vac Sci Technol, A8, 1990, 3186–3193

7159. A further study of the state of residual stress in TiN films made by physical vapor deposition methods: AJ Perry, J Vac Sci Technol, A8, 1990, 3186–3193

7448. The state of residual stress in TiN films made by physical vapor deposition methods; the state of the art: A J Perry, J Vac Sci Technol, A8, 1990, 1351–1358

7448. The state of residual stress in TiN films made by physical vapor deposition methods; the state of the art: A J Perry, J Vac Sci Technol, A8, 1990, 1351–1358

A further study of the state of residual stress in TiN films made by physical vapor deposition methods

The residual stress and strain distribution in TiN films deposited by chemical vapor deposition onto cemented carbide and physical vapor deposition methods onto cemented carbide and stainless steel are studied. Two sets of samples were chosen for study which, respectively, have either strong (111) textures or show different textures apparently resulting from different deposition rates. The data indicate that the residual stress on different planes in all samples, as measured by standard x-ray diffraction methods, is affected by the texture of the film. Reduction in the deposition rate increases the lattice distortion, reduces the strain distribution and the tendency of the (220) plane to show shear stress effects. The data confirm that studies of planes not lying parallel to the surface of the film are needed to allow a more complete characterization and to permit the way to a fuller interpretation to be opened.

The state of residual stress in TiN films made by physical vapor deposition methods; the state of the art

Existing transmission electron microscope studies indicate that a variety of lattice defects such as dislocation loops, ultramicrocracking, and trapped argon and its precipitation can be present in thin TiN films, where the precise defects observed in a given sample depend on the deposition conditions of the film. There are also changes in texture and grain size as the film thickness increases. A considerable amount of data has also been reported on the lattice parameters, diffraction peak widths (which indicate the strain distribution), and x-ray diffraction (XRD) residual stress, which are all found to depend strongly on the deposition conditions of TiN films. These properties also change through the thickness of the film. In the present work, existing XRD data and their trends are reviewed. While it is clear that correlations exist between the XRD data and microscopic and microstructural changes, it is not yet possible to relate them to specific microstructural features or lattice defects. The state of residual stress and the strain distribution are different on different planes in a given film. They also appear to be affected by texture and by the nature of the substrate in a way that cannot yet be classified.

The residual stress in TiN films deposited onto cemented carbide by high-rate reactive sputtering

The lattice parameters, lattice strain distribution and residual stress on different planes in tiN films deposited onto cemented carbide by reactive sputteringsputtering are studied by X-ray diffraction methods as a function of sputter target input power at a constant bias voltage of –100 V. The residual stress shows remarkably large differences between the values measured on different planes in a film. The form of the various sin 2ψ vs. lattice parameter plots (sspp) also shows differences and can, for example, be linear for the (422) peak but shows ψ splitting for the (220) peak. These results together with differences in the behavior of the parameters and diffraction peak broadening allow two distinct types of behavior to be isolated. They are not understood but are conjectured as being related to plastic flow, lattice deffects and possibly even ultramicrocracking on specific lattice planes.

Stress control in reactively sputtered AlN and TiN films

Al and Ti planar magnetron targets have been sputtered in Ar/N2 mixtures to deposit AlN and TiN films on unheated substrates; rf and dc discharges were used for the AlN and TiN deposition, respectively. The N2 flow was always sufficient to produce a nitrided target layer and x-ray diffraction showed single-phase films of AlN and TiN1.2. In N2 discharges, the AlN film stress varied from −19 GPa (compressive) to +2.5 GPa (tensile) as the pressure increased from 0.2 to 5 Pa. Intrinsic tensile stress in reactively sputtered compound films has not previously been reported. A similar change was observed in the stress of TiN films. Zero-stress AlN and TiN films were obtained at ∼1 Pa for the sputtering conditions used. The rapid decrease in compressive stress with increasing pressure is associated with a rapid decrease in both target voltage (for constant applied power) and deposition rate. Calorimetry measurements of the power flux at the substrates show an increase with pressure. With increasing Ar content, at a constant pressure, the compressive stress decreases although the target voltage and deposition rate increase; the substrate power flux decreases. The surface coverage of N on the targets increases with increasing N2 pressure because the N+2 flux increases. The compressive stress is probably due to bombardment of the film by neutral N atoms reflected with high energy from the targets. The decrease in deposition rates and increase in substrate power density may result from increased sputtering rates of N atoms from the target with a consequent decrease in metal atom sputtering.