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We report the structural and optical properties of InN films on Si(111) prepared by ion-beam-assisted filtered cathodic vacuum arc technique. X-ray diffraction and Raman spectroscopy measurements indicated that all the InN films were hexagonal crystalline InN. The InN films deposited at substrate temperature of 475 °C exhibited highly (0001) preferred orientation and texturing (cratered) surface morphology. The oxygen incorporated in the InN films was segregated in the form of amorphous indium oxide or oxynitride phases at the grain boundaries. Photoluminescence emission of ∼ 1.15 eV was observed at room temperature from the InN films.

A filtered cathodic vacuum arc technique has been applied to synthesis iron-nitride thin films on silicon (100) substrate. Two approaches were carried out to introduce the nitrogen gas into the chamber to control the nitrogen content. Films with smooth surface containing α-Fe(N), α′-Fe(N), αʺ-Fe 16 N 2 , γ′-Fe 4 N, ζ-Fe 2 N, ɛ-Fe 3 N and γʺ-FeN phases have been obtained, respectively. The magnetic properties of the films show that small amount of nitrogen addition into the iron films increases the saturation magnetization, while excess nitrogen decreases the saturation magnetization. It is explained based on the bond-band-barrier correlation mechanism [C.Q. Sun, Prog. Mater. Sci. 48 (2003) 521] that the electronegative nitrogen changes the valence states of iron into Fe + or Fe dipoles with higher magnetic momentum compared with an neutral Fe atom in the bulk.

A radius of curvature technique was used to study stresses in zinc oxide (ZnO) films prepared by filtered cathodic vacuum arc. To deposit the films, a pure zinc target was used and O 2 was fed into the chamber. It was found that stresses in ZnO films are strongly correlated to the growth parameters of substrate temperature, substrate bias and oxygen pressure. The films prepared for studying the effect of substrate bias and oxygen pressure exhibited only compressive stress. For the films prepared to investigate the effect of substrate temperature, a transition from compressive to tensile stress was observed when the temperature was varied from 100 to 420 °C. The tensile stress is attributed to thermal stress caused by the difference in thermal expansion coefficients of the film and the substrate. Atomic force microscope images of the films were obtained to study their surface morphology. It is found that the surface morphology is significantly influenced by the growth parameters.

An off-plane filtered cathodic vacuum arc (FCVA) system has been developed to deposit large area (up to 8 inch) optical coatings with good uniformity controlled by scanning magnetic field system. With this FCVA system, aluminium oxide thin films were deposited with high deposition rate (1.5-0.5 nm/s) on Si (100) and quartz substrates at room temperature under different oxygen pressures (1×10−2–3.73×10−2 Pa). The evolution of Al 2p core level and oxygen concentration in the films was studied by XPS spectra. In addition to the good uniformity (±2%) in terms of thickness and smooth surface (RMS: approx. 0.1 nm), the as-grown films were amorphous with low stress (less than 0.5 GPa). The variation of deposition rate with oxygen pressure was investigated. Optical properties, such as film transmittance and optical constants of aluminium oxide thin films formed under different oxygen pressures were determined. Film properties demonstrate the potential applications for aluminium oxide thin films in optical coatings and for FCVA technology in deposition of metal oxide optical coatings.

Passive devices using metal containing amorphous (a-C) films have been successfully fabricated. However, difficulties in the etching of these films as well as their inferior inertness compared to pure a-C films led us to study the electrical and optical properties of pure a-C films. The films were deposited using a filtered cathodic vacuum arc system (FCVA) in conjunction with high substrate pulse biasing. It is possible to control the sp2 content and hence the properties, by varying the substrate pulse bias voltage. In this study, the a-C films were prepared by varying the high substrate bias between 3 and 11 kV using a Plasma immersion ion implantation (PI3) system. Characterization of these samples gives us an indication about the suitability of the films for integrated passive devices and other applications. Four-point probe measurement has been carried out to study the resistivity of the films deposited on quartz and SiO2. The resistivity decreases with increasing pulse bias voltage, which is likely attributed to the sp2 fraction in the film as well as the substrates’ resistivity. The sp2 content in the films is estimated using XPS and Raman spectroscopy. Optical properties of the films are characterized using spectroscopic phase-modulated ellipsometry. The band gap decreases from 2.3 to 1.49 with increasing bias voltage.

The filtered cathodic vacuum arc technique was employed to deposit magnetic films such as FeNi on silicon substrate. Using the normal cathode design, tetrahedral amorphous carbon and metals films can be deposited. If a magnetic target is used, the arc spot always preferably moves to the edge of the target and then extinguishes. Therefore, the arc is not stable and no film can be deposited. A cathode was designed to obtain stable and continuous arc and uniform erosion pattern. The atomic force microscopy, grazing X-ray diffraction and vibrating sample magnetometry were used to characterize the morphological, structural and magnetic properties of the FeNi film. When the film deposited at substrate bias of −100 V, it exhibits a square magnetization–hysteresis loop, the lowest coercivity and the highest saturated magnetization among all the investigated samples, which may be related to its good surface roughness and crystallinity.

An investigation has been carried out to study the effect of frequency and pulse width on the deposition rate, intrinsic stress, morphological, micro-structural, mechanical and adhesive behaviour of tetrahedral amorphous carbon (ta:C) films prepared by a Filtered Cathodic Vacuum Arc (FCVA) system in conjunction with substrate pulse biasing. It is observed that the deposition rate increases with increasing frequency and pulse width in the lower ranges before it reaches to a more or less steady value of 25 nm/min at higher frequencies and pulse widths. The intrinsic stress in the film is reduced to a greater extent by the application of substrate pulse biasing. A stress reduction of approximately 85% can be easily obtained with an on-time (duty cycle) of 0.125%. The stress reduces further with increase in on-time, but at a slower rate. The morphological surface roughness increases with both frequency and pulse width. The micro-structural evaluation of the film using visible Raman spectroscopy shows that the intensity ratio of D-peak to G-peak ( I D / I G ) increases with increasing frequency. It is also observed that the G-peak width (FWHM) and the stress display a second order logarithmic correlation. The hardness shows a decrease in trend with increasing frequency. A noticeable increase in adhesion (critical load) with frequency is also observed in the lower ranges.

Titanium-containing diamond-like carbon films were deposited on silicon wafer substrates at room temperature by the filtered cathodic vacuum arc technique. A wide range of negative bias voltage from 0 to 500 V was applied to the substrates during film deposition. The structural and mechanical properties of the films were analysed by Rutherford backscattering spectroscopy, Raman spectroscopy, surface profilometry, the scratch test, and nanoindentation. For comparison, a set of pure diamond-like carbon films were also deposited and analysed. Raman spectra showed that all the samples had the lowest intensity ratio of the D peak to G peak ( I D / I G ) at a bias voltage of approximately 80 V, which normally represents the highest sp 3 -bonded carbon components in the films. Correspondingly, the highest internal stress (σ), hardness ( H ) and Young's modulus ( Y ), and the lowest scratch critical load ( L c ) were observed at the bias voltage of approximately 80 V. With the increase of titanium content in the films, I D / I G increased, while σ, H , and Y reduced, and L c increased. The results demonstrate that the addition of titanium into the diamond-like carbon films could significantly reduce the internal stress and, as a consequence, effectively improve the adhesion properties of these films.

Tetrahedral amorphous carbon (ta-C) and metal-containing amorphous carbon (a-C/Me) films including a-C/Ni, a-C/Fe and a-C/Al films were deposited using metal–carbon composite targets, by a filtered cathodic vacuum arc (FCVA) technique. The wettability of the films was examined by the contact angle measurement. Three types of liquid with different polarity were used to study the changes in the surface energy including the dispersive and polar components. Micro-Raman spectroscopy and X-ray induced photoelectron spectroscopy were used to characterize the structural and surface properties of the films. Atomic force microscopy (AFM) was used to characterize the morphology and roughness of the films. The contact angle decreases after incorporating Ni into the films. However, the contact angle of films increases after incorporating Fe and Al into the films, respectively. The contact angle of a-C/Al film with water reaches as high as 104°. The roughness of the films has no obvious effect on the contact angle. The structure and surface analysis show that the surface energy is related to sp 3 /sp 2 content in the film. The surface adsorption plays an important role in the change of the surface energy.

Polycrystalline ZnO films have been deposited by filtered cathodic vacuum arc with various substrate temperatures and bias voltages. The films deposited at room temperature are amorphous. The films grown at 230 and 430°C oriented in the (002) and (103) directions. Strong near-band edge room temperature photoluminescence emission has been observed in the film deposited at 230°C under floating bias. This is attributed to the reduced oxygen vacancies as determined by Raman spectroscopy. The bias voltage and high substrate temperature (up to 430°C) will induce more defects, resulting in broad band tails near the band edge. The optimized ZnO film has a transmittance which is over 80%.

Hard carbon films have been synthesized by heat-treating a polymer-poly(phenylcarbyne) at various temperatures (800–1100°C) for different times (0.5–2 h) in Ar ambient. The influences of heat-treatment temperature and time on the structural and tribological properties of the hard carbon films on graphite substrate were investigated by Raman spectroscopy, scanning electron microscopy (SEM), nanoindenter and pin-on-disk tribometer. The position of D bands and the relative intensity ( I D / I G ) of D and G band in the Raman spectra are related to the heat-treatment temperature and time. The hardness is approximately 6–8 GPa, which is lower than that of diamond like carbon (DLC) films (10–20 GPa) and higher than that of glassy carbon (3 GPa). The evolution of the coefficient of friction for the hard carbon films against sliding distance is similar to the DLC and not graphite-like carbon. The coefficient of friction is in the range from 0.14 to 0.19 at room temperature and a relative humidity of 40%. The wear rate is approximately 10 −15 m 3 N −1 m −1 . The hardness, coefficient of friction and wear rate are all dependent on the heat-treatment temperature and time. From the SEM, it was found that the soft graphite substrate makes the films crack at the edge of wear track but the spallation does not occur due to their strong adhesion.

The deposition of stoichiometric aluminum oxide films by off-plane double bend filtered cathodic vacuum arc (FCVA) is first reported. A novel method for introducing a reactive gas such as oxygen into the deposition chamber is presented. As a result, high deposition rate was made possible by this FCVA technique. Stoichiometric aluminum oxide films were deposited successfully under varying arc current and oxygen partial pressure. In general, a higher partial pressure is needed at higher arc current in order to maintain stoichiometric composition. The utilization efficiency of the aluminum target was also studied.

(Ti, Al)N films were deposited by a new off-plane double bend filtered cathodic vacuum arc technique under a nitrogen atmosphere. The substrates were held at ambient temperatures during the deposition of (Ti, Al)N films. Atomic force microscopy and X-ray diffraction were used to characterize the structure of the films. The internal stress, micro-hardness and Young's modulus were also studied. All (Ti, Al)N films deposited were atomic smooth. The surface roughness increases with increasing nitrogen pressure. The crystal structure, internal stress and mechanical properties of (Ti, Al)N films are strongly dependent on the nitrogen partial pressure. At lower nitrogen pressure, the structure of (Ti, Al)N films is composed of (Ti, Al)N phase, metal-rich nitride phase and metallic phase. The deposited films show (111) preferred orientation growth. With increasing nitrogen pressure, the structure change to single fcc type (Ti, Al)N phase, and a mixed (111) and (220) orientation was observed. Further increase of nitrogen pressure causes the disappearance of (Ti, Al)N phase and the formation of porous films. The hardness and Young's modulus of (Ti, Al)N films increase to a maximum at the pressure of 1.98×10−1 Pa, then decrease with increasing nitrogen pressure. The variation trend of internal stress in the films with nitrogen pressure is the same as that of hardness.

The influence of energetic Au + beam implantation on tetrahedral amorphous carbon (ta-C) films prepared by the filtered cathodic vacuum arc technique was studied. The ta-C films were implanted by 2 MeV Au + with dose varying from 10 12 –3×10 14 cm −2 . The as-deposited and ion implanted films were characterized using atomic force microscopy, Raman spectroscopy and ellipsometry. All films have a smooth surface morphology with RMS roughness less than 0.3 nm over an area of 1 μm 2 . The Raman spectra of the as-deposited and ion implanted films all show a G peak at approximately 1565 cm −1 and a D peak at approximately 1395 cm −1 . The intensity ratio of the D to G peak, I D / I G , remains unchanged (∼0.50) for films implanted with an ion dose below 10 13 cm −2 , and increases to 2.10 for the film implanted with an ion dose of 3×10 14 cm −2 . The Tauc optical band gap decreases from 2.05 eV for the as-deposited film to 1.40 eV for the film implanted with an ion dose of 10 13 cm −2 , and becomes very close to zero for the films implanted with an ion dose greater than 3×10 13 cm −2 . Both Raman and ellipsometric results show that a large percentage of carbon atoms become sp 2 -bonded in the films implanted with large ion doses.

Nitrogenated, tetrahedral amorphous carbon (ta-C) films prepared by the filtered cathodic vacuum arc (FCVA) technique have been studied using ultraviolet (UV, 244 nm) and visible (514 nm) micro-Raman scattering. The nitrogen ions were produced by a RF ion-beam source with a nitrogen flow-rate varying from 0 to 10.0 sccm, which results in a nitrogen content from 0 to 10.8 at.% in the deposited films. In the visible Raman spectra, only vibrational modes of sp 2 -bonded carbon (G and D peaks) are observed, while a new wide peak, called the T peak, located at 1090‐1320 cm 21 , associated with the vibrational mode of sp 3 -bonded carbon, appears in the UV-Raman spectra. In the visible Raman spectra, the G-peak width (100‐113 cm 21 ) and the intensity ratio ID/IG (0.34‐0.94) are both sensitive to the structural changes induced by N incorporation. In the UV-Raman spectra, the G-peak position almost linearly decreases from 1665 to 1610 cm 21 , and the Tpeak position increases tremendously from 1095 to 1314 cm 21 with increasing N content. The G-peak position and width, and the T-peak position, are all sensitive to the bonding structure of the films. q 2000 Elsevier Science S.A. All rights reserved.