Reactive Magnetron Sputtering Method Research Articles

Superhard Nb–Si–N composite films synthesized by reactive magnetron sputtering

Abstract By means of the reactive magnetron sputtering method, a series of Nb–Si–N composite films with different Si contents were deposited in an Ar, N2 and SiH4 mixture atmosphere. These films’ chemical composition, phase formation, microstructure and mechanical properties were characterized by the energy dispersive spectroscopy, X-ray diffraction, transmission electron microcopy, atomic force microscopy and nanoindentation. The experimental results showed that the silicon content in the Nb–Si–N composite films can be conveniently controlled by adjusting the SiH4 partial pressure in mixed gas. The hardness and elastic modulus of the Nb–Si–N films were remarkably increased with a small amount of silicon addition and reached their maximum values of 53 and 521 GPa, respectively, at 3.4 at.% Si. Such an obvious enhancement of mechanical properties is related to the increment of crystal defects in the Nb–Si–N films. With silicon content increasing in the films further, the mechanical properties decreased gradually to somewhat a bit lower than those of the NbN film.

An anode with aluminum doped on zinc oxide thin films for organic light emitting devices

Doped zinc oxides are attractive alternative materials as transparent conducting electrode because they are nontoxic and inexpensive compared with indium tin oxide (ITO). Transparent conducting aluminum-doped zinc oxide (AZO) thin films have been deposited on glass substrates by DC reactive magnetron sputtering method. Films were deposited at a substrate temperature of 150 °C in 0.03 Pa of oxygen pressure. The electrical and optical properties of the film with the Al-doping amount of 2 wt% in the target were investigated. For the 300-nm thick AZO film deposited using a ZnO target with an Al content of 2 wt%, the lowest electrical resistivity was 4 × 10 −4 Ω cm and the average transmission in the visible range 400–700 nm was more than 90%. The AZO film was used as an anode contact to fabricate organic light-emitting diodes. The device performance was measured and the current efficiency of 2.9 cd/A was measured at a current density of 100 mA/cm 2.

Study of the deposition parameters and Fe-dopant effect in the photocatalytic activity of TiO 2 films prepared by dc reactive magnetron sputtering

The reactive magnetron sputtering method was used to prepare pure and Fe-doped titanium dioxide thin films. The films were deposited onto microscope glass slides and polycarbonate plates at different total pressure and Fe-doping concentrations. The films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and UV-visible spectroscopy (UV). For glass substrates a polycrystalline TiO 2 structure was verified with X-ray diffraction, which showed typical characteristic anatase reflections. An iron phase appeared in the highly Fe-doped samples. The absorption edges of the Fe-doped TiO 2 films shifted to visible region with increasing concentration of iron. For the polycarbonate substrate an amorphous TiO 2 structure was revealed for all deposition conditions. The effects of different Fe-doping and total pressure levels on the photocatalytic activity were obtained by the degradation rates of Rhodamine-B ( RoB) dye under UV light irradiation. For the deposition conditions considered in this study the highest photodegradation rates were achieved for films deposited on the polymer substrates. Of these overall highest rates was achieved for deposition at 0.4 Pa and without doping. However, for both substrates, films prepared at the particular total pressure of 0.5 Pa and a low iron concentration showed better photocatalytic activity than the pure TiO 2 films prepared under the same deposition parameters. On the contrary, the photocatalytic degradation rates of RoB on the highly Fe-doped TiO 2 films decreased strongly.

고주파용 CoFeAlO계 박막의 자기적 특성

The influence of partial pressure on saturation mgnetization, coercivity, anisotropy field and effective permeability (over 1GHz) of as-deposited Co-Fe-Al-O thin films, which were fabricated by RF magnetron reactive sputtering method, were investigated. The thin film fabricated at partial pressure of 4% exhibits the best magnetic softness with saturation magnetization 4Ms of 18.1 kG, coercivity of 0.82 Oe, anisotropy field () of Oe, and effective permeability () about 1,024 above 1 GHz. the electrical resistivity of Co-Fe-Al-O thin films were increased with increasing partial pressure, the electrical resistivity of thin film with the best soft magnetic properties was 560.7 am. Therefore, It is assumed that the good soft magnetic properties of thin film results from high electrical resistivity and large anisotropy field.

Study of the electronic paraprocess and antiphase boundaries as sources of the demagnetisation phenomenon in magnetite

In this paper, a detailed study of the magnetic behaviour particularly at the Verwey transition is presented for some stoichiometric magnetite samples, as a function of their shape (film/bulk) and crystalline structure (single/polycrystal). Travelling solvent floating zone technique was first used to obtain crystalline bulk magnetite samples (1 1 0) oriented, while molecular beam epitaxy allowed us to grow a 68 nm Fe 3O 4 (1 1 1) crystalline film on α -Al 2O 3(0 0 0 1) substrate. A 64 nm Fe 3O 4 polycrystalline film grown on an Si/SiO 2 substrate using DC reactive magnetron sputtering method completed the sample series. An anomalous magnetisation behaviour has been evidenced in the Verwey temperature vicinity that is shown to depend on the applied magnetic field. A magneto-electronic model explains the origin of this behaviour. The maximum in the demagnetisation at the Verwey transition has been noticed very near 0.1 T (i.e. 90 kA/m, as found out on bulk magnetite). The amount and nature of structural defects have been proven to be determinant in the magnetisation process, and the approach to saturation is well described by the M = M S ( 1 - b / B n ) relation, with n = 2 in bulk magnetite crystal and n = 0.5 in epitaxial magnetite film, even across and below the Verwey transition after paraprocess corrections. These dependences exist in the 10–300 K temperature range, excluding isotropic point (near 130 K), and demonstrate that the antiphase boundaries (APBs) are responsible for the much more progressive approach to saturation observed in thin films than in bulk samples which is consistent with previous observations. On the epitaxial film, n is found to decrease down to 0.33 at isotropic point due to an enhanced super-exchange interaction through APBs.

Structure, chemical and phase compositions of coatings deposited by reactive magnetron sputtering onto the brass substrate

The paper presents investigation results of the structure, as well as of the chemical and phase compositions of the selected PVD coatings deposited with the reactive magnetron sputtering method. The 1, 15 and 150-ply Ti/CrN, Ti/TiAlN, Ti/ZrN, TiAlN/Mo coatings and the mono-layer Cr/CrN, Zr/ZrN, Ti/TiN, TiAl/TiAlN ones were investigated, deposited onto the substrate from the CuZn40Pb2 brass. It was found out that the structure of the PVD coatings put down with the reactive magnetron sputtering method is composed of fine crystallites and that their average size is in the range of 50–250 nm, depending on the coating type. The duplex coating structure {1 1 1} and {1 0 0} or {1 1 0} and {3 1 1} occurs in most cases, which is a consequence of the many factors influencing the change of the resulting energy vector direction, according to which the condensate is oriented. The investigated mono-layer coatings demonstrate the columnar structure, which results in decreasing the corrosion resistance of the coatings. There is a strong relationship between the structure of the developed coatings and their functional properties.

Effect of nitrogen concentration on the magnetic properties of Fe-Ta-N thin films

Soft magnetic nanocrystalline thin films with a high content of Ta (10 wt %) are synthesized by the method of reactive RF magnetron sputtering with subsequent annealing. It is established that the microstructure and magnetic properties of the films depend on the nitrogen partial pressure during sputtering and on the annealing temperature. Annealing of the amorphous films leads to the formation of α-Fe nanocrystallites whose properties and interactions determine the film parameters. A decrease in the α-Fe grain size to a level below the length of ferromagnetic exchange interaction sharply increases the magnetic softness. The role of nitrogen ions in the formation of a α-Fe nanocrystallite structure and uniaxial magnetic anisotropy of Fe-Ta-N films is established. The optimum technological regimes of deposition and annealing of the Fe-Ta-N films are determined, which ensure the synthesis of Fe-Ta-N nanocrystalline thin films with a high magnetic softness (Bs=1.6 T, Hc=0.2 Oe, and μ1(1 MHz)=3400).

Synthesis and characterization of CN x/TiN multilayers on Si(100) substrates

CN x /TiN multilayer coatings were deposited onto Si(100) substrates by using the reactive closed-field unbalanced magnetron sputtering method. Different bilayer thicknesses ( B T) were attained by varying the substrate rotation speed during the deposition process. The focus of this work was a collective investigation of the bonding states and structure of the multilayer by means of X-ray photoelectron spectroscopy (XPS), high-angle X-ray diffraction (XRD), and low-angle X-ray scattering (LXRD). The characteristic of the layer was also confirmed by transmission electron microscopy (TEM), root-mean-square (RMS) surface roughness by atomic force microscopy (AFM). Chemical states such as TiN, TiO 2, and TiC exist in the TiN layer. The CN x layer consisted of C, N and Ti in which N is bonded with C in the forms of C N and C N. The RMS surface roughness of the multilayers significantly varied with the substrate rotation speed. The RMS surface roughness was between 0.7 and 1.4 nm. The hardness of CN x /TiN multilayer was highly dependent on their bilayer thickness. This multi-layer structure demonstrated an enhanced microhardness with decreasing bilayer thickness. It is found that for smaller bilayer thicknesses, the microhardness reproducibly achieved is as high as ∼50 GPa. In addition, stress measurement on the CN x /TiN multilayer is also conducted. The internal (compressive) stress is associated with the hardness of the multilayer. For the maximum hardness the stress is found to be ∼7.7 GPa. Moreover, pin-on disc test under dry condition showed low friction coefficient (0.11).

Titanium dioxide thin films: the effect of the preparation method in their photocatalytic properties

Titanium dioxide thin films were deposited by DC reactive magnetron sputtering and spray pyrolysis methods on glass and glass coated with fluorine tin oxide (FTO). The films were characterized by X-ray diffraction, scanning and transmission electron microscopy, atomic force microscopy and UV–vis spectroscopy. The influence of a reactive atmosphere: a 50/50 Ar–O 2 mixture on TiO 2 thin films deposited by sputtering has been studied following the evolution of surface and structural properties and has been correlated, when possible, with photocatalytic properties under UV illumination. Also transparent TiO 2 thin films have been prepared by spray pyrolysis using a low concentration of titanium precursor and different substrates temperatures. At higher substrate temperatures the films were polycrystalline in anatase phase; at lower substrate temperatures the films presented amorphous configuration. The best photocatalytic activity was found for films deposited by spray pyrolysis at T s = 450 °C and for those deposited by magnetron sputtering those deposited at 16 mTorr gave the higher photodegradation rates.

Erosion resistance and tribological properties of coatings deposited by reactive magnetron sputtering method onto the brass substrate

Monolithic nitride coatings and multilayer ceramic/metallic coatings were deposited onto brass (CuZn40Pb2) substrates by dc magnetron sputtering. The ceramic coatings or layers are Cr-, Ti-, TiAl-, Zr-nitrides. The mechanical properties, tribological behaviour were studied. To improve adhesion, a thin metallic layer was deposited prior to deposition of ceramic monolithic coatings. Two sets of multilayer coatings for each nitride family were produced. One of the sets with 15 monolayers and the other with 150 monolayers. The results show that all coatings demonstrate good adhesion. The optimum mechanical properties, tribological behaviour and wear resistance were obtained for the monolithic coatings with a thin intermediate metallic layer.

Influence of Ar ion-beam assistance and annealing temperatures on properties of TiO2 thin films deposited by reactive DC magnetron sputtering

TiO2 thin films were prepared by using a reactive DC magnetron sputtering method with Ar ion-beam assistance. The effect of the Ar ion-beam current on the structural and optical properties of the reactive magnetron sputtered TiO2 thin films was studied. The as-deposited films were subjected to annealing with the atmospheric environment, and the change of film properties after annealing was investigated. When the Ar ion-beam assistance was applied, the deposited TiO2 thin films were found to induce a higher deposition rate, a higher packing density and refractive index, a lower extinction coefficient, and a smoother surface than that of the film deposited without ion-beam assistance. The structures of all as-deposited films were amorphous. In the annealing process, the ion-beam-assisted TiO2 thin films had a phase transition from amorphous to anatase polycrystalline with a strong TiO2 anatase (101) peak at a temperature of 400 °C. At above 400 °C, the refractive index of deposited films increased by an anatase structure and the extinction coefficient increased due to a reduction in the oxidation of TiO2 thin films.

Aluminum nitride films deposited under various sputtering parameters on molybdenum electrodes

In this study, highly c-axis-oriented fine polycrystalline aluminum nitride (AlN) films are deposited on molybdenum electrodes using the reactive RF magnetron sputtering method. Molybdenum is adopted as the electrode material rather than the conventional choice of Pt/Ti, Au/Cr or Al because it has low resistivity, large acoustic velocity, and provides a good adhesion between the thin AlN film and the low-stress Si 3N 4 membrane. The influences of the RF power and nitrogen flow rate ratio on the crystalline orientation and surface morphologies of the deposited AlN films are thoroughly investigated. It was found that the AlN films prepared using the RF power of 400 W and an elevated N 2 flow rate ratio of 75% exhibit a greater tendency towards the preferred c-axis-orientation and exhibit smoother morphologies. Furthermore, thicker AlN films and the use of a higher RF power (400 W) in the deposition process tend to promote a narrower full width at half maximum. The experimental results demonstrate that the fabricated FBAR devices, its piezoelectric-active area (24774 μm 2) was polygonal shape with 5 sides of 120 μm, the thickness of low-stress Si 3N 4, AlN film, Mo (bottom) and Al (top) electrodes was consisted of 0.2 μm., 2.25 μm, 0.1 μm and 0.18 μm, respectively. The effective electromechanical coupling coefficient ( k eff 2 ) and the quality factor ( Q f x ) were about 1.5% and 312, respectively.

Application of the duplex TiN coatings to improve the tribological properties of Electro Hydrostatic Actuator pump parts

In this paper, the effects of duplex treatment consisting of plasma nitriding and PVD hard coating on the surface properties of EHA pump parts were investigated. Two different coatings (single-layered TiN coating and duplex TiN coating) were deposited on AISI 4340 steel using reactive unbalanced magnetron sputtering method. A high-speed disk-to-disk type wear tests under a mineral oil environment were performed and the results from various surface conditions were compared with each other. The duplex TiN coating has the lowest static friction coefficient of 0.04, while others indicated the almost identical values between 0.08 and 0.09. Especially, much improvement of starting and slow-running behavior in the Stribeck curve was obtained from the duplex TiN coating. Wear rate of the duplex TiN coating was reduced by a factor of 1.8 and an order of degree, compared with those of single-layered TiN and plasma-nitrided specimen, respectively. The critical load of duplex TiN coating (Lc) was measured to be approximately 38 N, which is approximately 2.5 times higher than that of single-layered TiN coating of 15 N. In addition, application of the duplex treatment on the commercial cylinder barrel against bronze valve plate showed much reduced friction coefficient up to 1200 rpm.

Effect of CH4partial pressure on the microstructure and mechanical properties of magnetron sputtered TiC films

TiC thin film has become one of the most frequently used hard coatings because of its high hardness (26– 31 GPa), good wear resistance, low coefficient of friction against steel, and other excellent properties [1]. It can be deposited by chemical or physical vapor deposition (CVD or PVD). TiC films manufactured by PVD have the advantages of low deposition temperature, high quality, and high deposition speed, etc. [2]. Reactively sputtered TiC films are deposited by using gases which contain carbon such as CH4 and C2H2. Compared with using highly active C2H2, the processing is better controlled by using CH4. In this paper, TiC thin films were deposited with reactive magnetron sputtering method at different CH4 partial pressures and the effect of CH4 on their phase, microstructure, and mechanical properties was investigated. TiC films were deposited on silicon substrates by using radio frequency (RF) magnetron sputtering at room temperature. The substrates were ultrasonically cleaned in acetone and alcohol and then mounted on the substrate holder in the vacuum chamber. To improve the adhesion, a metallic Ti layer with a thickness of approximate 200 nm was deposited prior to the deposition of the ceramic TiC films. The TiC films were deposited from a pure Ti target (99.99%) in an Ar and CH4 mixture atmosphere. The Ar partial pressure was kept at 0.3 Pa, while the CH4 partial pressure varied from 0.01 to 0.08 Pa. (The CH4 partial pressure was 0.01, 0.02, 0.04, 0.06 and 0.08 Pa; specimens were numbered from 1 to 5 respectively). During this study, the target power was kept at 200 W and the deposition time was 120 min for each specimen. The phase formation and microstructure of films were investigated by X-ray diffraction (XRD) using a Dmax-rC diffractor and transmission electron microscopy (TEM) using a JEM-100CX TEM. The morphology of films was observed using a Nanoscope IIIa atomic force microscope (AFM). Mechanical property measurements of TiC thin films were carried out using a Fischerscope HV100 microhardness tester and the results were checked by AFM. The XRD spectra of the TiC films deposited at different CH4 partial pressures are shown in Fig. 1. It can be seen that at the CH4 partial pressure of 0.01 Pa, the film mainly contains metallic Ti. When CH4 pressure increases from 0.02 to 0.04 Pa, the films are single phase fcc TiC. When the CH4 partial pressure is higher than

Effect of post-annealing treatments on the properties of Zn 1− xCd xO films on glass substrates

Ternary Zn 1− x Cd x O (0≤ x≤0.53) alloy crystalline films with highly (0 0 2)-preferred orientations have been prepared on glass substrates by using the dc reactive magnetron sputtering method and exposed to annealing treatments in O 2 ambient. The crystal quality of the annealed Zn 1− x Cd x O films improves much. As a case of the sample with x=0.53, the diffraction peaks in intensity attain maximum values at the annealing temperature of 500 °C. But for the samples with x≥0.53, the CdO phase separation and re-evaporation from the films are very serious. So for the Zn 1− x Cd x O films with higher Cd content, to prevent the segregation of CdO, the annealing temperature should be less than 400 °C, and the annealing time should be less than 1 h.

Effect of deposition methods on the properties of photocatalyticTiO2 thin films prepared by spray pyrolysis and magnetron sputtering

Titanium dioxide thin films were deposited by DC reactive magnetron sputtering and spraypyrolysis methods onto glass and glass coated with fluorine doped tin oxide (FTO).The films were characterized by x-ray diffraction, scanning electron microscopy,atomic force microscopy and UV–visible spectroscopy. For films deposited bythe sputtering technique we have studied the effect of the total pressure of anAr–O2 mixture on the substrate properties, on the deposition rate, phase composition,crystallinity, surface morphology and on the photocatalytic properties. Also transparentTiO2 thin films have been prepared by spray pyrolysis using a low concentration of titaniumprecursor with different substrate temperatures. At higher substrate temperatures the filmswere polycrystalline in the anatase phase; at lower substrate temperatures thefilms presented an amorphous configuration. The photocatalytic properties ofTiO2 thin films were tested with the degradation methylene blue under UVlight irradiation. The higher degradation rates were reached for filmsprepared by spray pyrolysis with a substrate temperature close to400 °C, and for a high total pressure (16 mTorr) for films deposited by DC magnetron sputtering.

High frequency characteristics and soft magnetic properties of FeCoBN nanocrystalline films

For developing magnetic materials working in GHz ranges, the soft magnetic properties and high frequency characteristics were examined in as-deposited FeCoBN thin films fabricated by a reactive rf magnetron sputtering method. As a result, these films exhibited high ferromagnetic resonance frequency of 1.5-4 GHz and good soft magnetic properties, such as 4πM s of 17 ∼ 21 kG, p of 50 ∼ 220 μΩ cm, He of 3-90 Oe and H k of 20-180 Oe. These magnetic properties of the films were discussed related to the microstructures.

Sputtering deposited ternary Zn 1− xCd xO crystal films on Si(111) substrates

Using the d.c. reactive magnetron sputtering method we have successfully deposited completely (002)-oriented ternary Zn 1− x Cd x O (0≤ x≤0.6) alloy crystal films without Cd segregation on Si(111) substrates. X-Ray photoelectron spectroscopy measurements show that Cd/Zn ratios in the films are nearly consistent with those in the targets. The Zn and Cd exist only in oxidized states, no evidence of metallic Zn or Cd was observed. The O/(Cd+Zn) atomic ratios of the films are in the range of 0.89–0.98. Transmission electron microscopy measurements show that for the (002)-oriented films the grains are columnar structures with the c-axis perpendicular to the Si substrate. By post-annealing treatments in O 2 ambient, the crystal quality of the Zn 1− x Cd x O films can be improved. For the sample of x=0.2, the optimal annealing temperature is 500 °C.

Electrical and optical properties of zinc oxide thin films grown by reactive magnetron sputtering method

ZnO is very interesting material for practical applications because of its high transparency in the visible light and simultaneously high electrical conductivity. In this paper, the ZnO films growth by a reactive magnetron deposition method is used to study the relationship between film parameters and preparation conditions. The influence of discharge power as well as total pressure and oxygen partial pressure on the deposition rate and electrical properties was studied. The p–n junctions were formed by ion-beam deposition of ZnO films on p-type silicon substrates.

Polycrystalline AlN films deposited at low temperature for selective UV detectors

Polycrystalline aluminum nitride (AlN) thin films were fabricated at 300°C by two different operating modes of magnetron reactive sputtering (RMS) method: radio-frequency (rf) and direct current (dc) RMS. The films obtained by the rf RMS are highly textured with (0 0 0 1) orientation and have columnar structure, and the films fabricated by the dc RMS have fibrous structure with crystallites oriented in ( 1 0 1 ̄ 0 ) and ( 1 1 2 ̄ 0 ) plans. Both types of AlN films are sensitive to UV radiation and the photo-conductivity decreases rapidly with increasing wavelength (by more than four orders of magnitude from 200 to 400 nm). The optical and electrical properties of both types of films are comparable, but the columnar grain structure of the first type may lead to enhanced dark currents in sandwich structure devices, so that the second type of films seems to be more appropriate for this kind of devices.