Planar Magnetron Sputtering System Research Articles

Target utilization of planar magnetron sputtering using a rotating tilted unbalanced yoke magnet

The dependence of the magnetic flux density, erosion uniformity, and target utilization on the yoke magnet tilt angle was investigated in a planar magnetron sputtering system, using a rotating, tilted, unbalanced, asymmetrical magnet. In these experiments, circular and elliptical outer yokes were used as the rotating yoke magnet. The magnetic flux density distributions were measured two-dimensionally on the target surface and compared with the erosion uniformity. As the yoke magnet tilt angle increased, the magnetic flux density distribution expanded and became more uniform, and the eroded areas expanded toward the outside of the target surface. With a circular outer yoke, as the yoke magnet tilt angle increased from 0° to 8°, utilization of a 5-inch target linearly increased from 60 to 80%. On the other hand, with an elliptical outer yoke, the utilization of the target was approximately 70%, regardless of the yoke magnet tilt angle. This is because, as the tilt angle is increased, the inner area of the target eroded more deeply, while the outer area eroded less deeply. The deposition rate when using the elliptical outer yoke was 1.2 times faster than that of when using the circular outer yoke at the same magnet tilt angle. By decreasing the magnetic flux density on the inner area of the target with an elliptical outer yoke magnet, a higher deposition rate may be obtained than is observed with a circular magnet, and target utilization of over 70% can be achieved.

Deposition of Photocatalytic TiO2 Films by Planar Magnetron Sputtering System with Opposed Ti Targets

TiO2 films are deposited on glass substrate in O2/Ar gas mixtures by facing target planar magnetron (FT-PM) sputtering, and the effects of the sputtering system on the crystal phases and axis orientation of TiO2 films are investigated for as-deposited films. Deposition is carried out by two systems: In the first system the opposing magnets have opposite polarites of internal permanent magnets in each target holder; this leads to confinement of the electrons therefore weak electron bombardment on the substrate. The result is poor grain growth with low quality anatase films with poor photocatalytic activity. In the second system the opposing magnets have the same polarities each other; the electron bombardment becomes strong and grain growth is enhanced. The results indicate a high quality anatase film with very good photocatalytic activity. [DOI: 10.1380/ejssnt.2009.290]

Ag/PEO nanocomposite fabricated in a planar magnetron sputtering

Thin films of silver (Ag)/polyethylene-oxide (PEO) nanocomposite were fabricated by a co-deposition of Ag sputtering particles and PEO thin film on substrates using a planar magnetron sputtering system. The PEO were polymerized from the monomer ethyl glycol dimethyl ether in the magnetron sputtering (MS) plasma. The nanocomposites were characterized by using UV-visible spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and atomic force microscopy (AFM). The correlation was performed between the concentrations of Ag and functional group density in Ag/PEO nanocomposites with the discharge parameters, such as sputtering gas pressure and the distance of target-to-substrate. By using AFM and XRD, it is illustrated that the Ag particles distribute uniformly in the body of nanocomposite and remain in atomic status with preferential growth in facet of (111).

Electrical properties of indium-tin oxide films deposited on nonheated substrates using a planar-magnetron sputtering system and a facing-targets sputtering system

Distribution of the electrical properties of indium-tin oxide (ITO) film prepared by both a planar-magnetron sputtering system (PMSS) and a facing-targets sputtering system (FTSS) at room temperature were investigated. It was found that the outstanding non-uniformities of the electrical properties in noncrystalline ITO films are mainly due to the variation of the oxygen stoichiometry dependent on film positions on substrate surfaces. Furthermore, ITO film with uniform distribution of electrical properties was obtainable using FTSS.

Transparent Flexible Substrates Based on Polyimides with Aluminum Doped Zinc Oxide (AZO) Thin Films

In this paper, transparent flexible substrates based on polyimides (PIs) with aluminum doped zinc oxide (AZO) thin films for organic electroluminescent devices have been prepared. PI film based on 2,2'-bis-(3,4-dicarboxyphenyl) hexafluoropropanedianhydride (6FDA) and 2,2'-bis-(trifluoromethyl)-4,4'-diaminobiphenyl (TFDB) were used for transparent flexible substrates. AZO thin films were prepared at two substrate deposition temperatures of 100/spl deg/C and 200/spl deg/C with a typical radio-frequency (r.f.) planar magnetron sputtering system. The sheet resistance and the optical transmission properties for AZO films on the fluorinated PI substrate were comparable with those for the AZO films on a glass substrate. The substrate properties were better when the deposition temperature was higher.

Polyimide as a Plastic Substrate for the Flexible Organic Electroluminescent Device

AbstractIn this work, transparent flexible substrates based on polyimides(PI) with indium tin oxide (ITO) thin films for organic electroluminescent devices have been prepared. 2,2'-bis-(3,4- dicarboxyphenyl) hexafluoropropanedianhydride (6FDA) and 2,2'-bis-(trifluoromethyl)-4,4'- diaminobiphenyl (TFDB) PI films were used for transparent flexible substrates. ITO thin films were prepared at two substrate deposition temperatures of 25°C and 150°C with a typical radio- frequency (r.f.) planar magnetron sputtering system. The sheet resistance and the optical transmission properties of the fluorinated PI substrate were comparable with those for the slide glass substrate. The substrate properties are better when the deposition temperature is higher. SiO2 coating onto the fluorinated PI substrate by sol-gel reaction was also attempted to improve the optical transmission of the ITO/PI substrate. It was found that the coating of SiO2 affected on the morphology of the PI substrates.

多重磁極マグネトロンスパッタリング法で作製したＦｅ‐Ｎ薄膜の磁化特性と膜構造

Thin films of Fe and Fe-N have been prepared using an rf magnetron sputtering system equiped with multipolar magnetic plasma confinement (MMPC), which is efficient for preparation of ferromagnetic thin films at low pressures. For sputtering with 150 W rf-power, the deposition rate of Fe film is 12-14 nm/min, which is three times larger than that of conventional planar magnetron sputtering system. Iron nitride films have been sputter-deposited in an Ar-N2 gas mixture at several pressures, Psp, of 5-0.6 mTorr and the gas flow ratio, fN2 = N2/(Ar + N2), of 0-0.6. The crystalline and morphological structures, the nitrogen content in the film, and the resistivity depend strongly on Psp and fN2. These dependences are explained by the energy of sputtered particles reached at the film surface. In particular, the films prepared at 0.6 mTorr, which is realized by MMPC method, exhibit the crystalline structures of Fe, Fe4N and Fe3N phases depending on fN2, and show the very high purity.

PREPARATION AND CHARACTERIZATION OF ITO-COATED COLORLESS POLYIMIDE SUBSTRATES

In this work, aliphatic cyclic polyimide (alicyclic PI) was synthesized from alicyclic dianhydride and was used as a flexible transparent substrate for the deposition of ITO thin films. ITO thin films were prepared at typical high substrate deposition temperature with a typical r.f. planar magnetron sputtering system. The optical transmission of ITO/PI in the visible light range is slightly increased with the increase of the substrate temperature. The sheet resistance of the ITO films deposited onto the PI substrate is significantly decreased with the increase of the substrate deposition temperature. The electrical sheet resistance is slightly proportional to the surface roughness of the ITO films.

Effect of sputtering gas pressure and nitrogen concentration on crystal orientation and residual stress in sputtered AlN films

The crystal orientation and residual stress in sputtered AlN films were investigated by X-ray diffraction. The AlN films were deposited on a glass substrate by direct current (DC) and radio frequency (RF) planar magnetron sputtering system at mixed gas of argon and nitrogen under various sputtering gas pressures ( P) and nitrogen concentrations ( C N). The following results were obtained: (1) the degree of the c-axis orientation of AlN films deposited by RF sputtering was superior to those produced by DC sputtering; (2) the degree of the c-axis orientation of AlN films was improved with decreasing P and increasing C N; (3) in-plane large compressive stress was obtained at low P, and in-plane tensile stress was obtained at high P ( P>1.3 Pa); (4) film produced by DC sputtering at low P ( P<1 Pa) extensively included micro-cracks; and (5) in-plane tensile stress was obtained at low C N and large compressive stress was obtained at C N ( C N>40%).

Amorphous ZnO–In 2O 3 transparent conductive films by simultaneous sputtering method of ZnO and In 2O 3 targets

Ternary compound films of ZnO–In 2O 3 were deposited using an opposed DC planar magnetron sputtering system. The phase change and electrical properties of the Zn–In oxide films were investigated over a wide range of ratio of Zn to In. Impurities of Al and Sn were intentionally added to the films in order to investigate the influence of these impurities on the above properties. A low-resistivity amorphous film was formed by adding Al at substrate temperatures of below 250°C. At 150°C, amorphous phase film was obtained at a wide range of ratio of Zn to In and the minimum resistivity was 4×10 −4 Ω cm. It was found that the addition of Al or Sn impurities enlarged the level of Zn content wherever the amorphous structure appears. Doping effect of Al and Sn for homologous phase was not observed. However, in amorphous phase ZnO–In 2O 3, the addition of Al and Sn did not increase resisitivity when the ratio of Zn to In was at the level corresponding to ZnIn 2O 4, Zn 2In 2O 5 and Zn 3In 2O 6 in a crystalline homologous phase.

CdS and CdTe large area thin films processed by radio-frequency planar-magnetron sputtering

We present in this work the processing of large area CdS and CdTe thin films. We have been working for this purpose with a Radio-Frequency Planar Magnetron Sputtering (RF-PMS) system with two 6-inch balanced guns, processing thin films in areas as large as 450 cm 2 grown on soda-lime glasses. Conducting glasses (SnO 2 of 7 Ω/□) were also used only for CdS deposition in order to further analyze the heterojunction CdS/CdTe. The best films have been processed with substrate temperatures ( T s ) of 250°C for CdS and 215°C for CdTe; Ar chamber-pressure of 20 mtorr, radio frequency power of 300 W, and different deposition time between target materials.

CdS and CdTe Large Area Thin Films Processed by Radio-Frequency Planar-Magnetron Sputtering

ABSTRACTThe processing of large area thin films solar cells represents a challenge, mainly due to the need for optimal setting of the critical growth parameters for scaling-up of the processes that guarantee homogeneous properties in the sub-minimodule architecture. We have been working with a Radio-Frequency Planar Magnetron Sputtering (RF-PMS) system, processing 450 cm2 areas of CdS and CdTe thin films grown on soda lime glasses and conducting glasses (SnO2:F-7ω/ ) for CdS, using for it a 6” balanced gun. The films have been processed with substrate temperatures (Ts) of 250°C, Ar chamber-pressure of 20 mTorr, and radio frequency power of 300 watts. The films were characterized by morphological, optical and electrical techniques, presenting in this work the corresponding measurements. Our results show that the better polycrystalline perfection, adherence and pinhole free films are obtained at substrate temperatures of 250°C.

Fabrication and characterization of PZT thin film ultrasonic devices

The purpose of this study was to fabricate and analyze high sensitivity PZT thin film ultrasonic sensors. In this experiment, PZT material, silicon substrates and the RF planar magnetron sputtering system were adopted to deposit PZT thin films onto silicon diaphragms for ultrasonic sensors. Experimentally, the sensitivity of the devices was measured for frequencies ranging from 100KHz to 4MHz, where the maximum transmission and reception sensitivities were 74 μBar/ dBV and ‐68dBV/ μBar at 4 MHz. The sensitivity increased at higher frequencies, indicating that the PZT thin film ultrasonic devices are suitable for application as ultrasonic wave sensors at high operating frequencies. The experiment also demonstrated that the fabricated ultrasonic devices with poled PZT thin film have better transmission and reception responses than devices with unpoled PZT thin film.

Langmuir probe measurements of plasma parameters in a planar magnetron with additional plasma confinement

Langmuir probe measurements have been carried out in a planar magnetron sputtering system with an additional plasma confinement which can be operated at low argon pressures (down to 3.4×10 −2 Pa) when target utilization greater than 80% can be achieved. The electron density, electron temperature, relative densities of low- and high-energy groups of electrons and the difference between the plasma and floating potential have been determined in various positions between the target and a substrate at the argon pressures in the range from 0.05 to 5 Pa. It has been proved that the additional magnetic field results, particularly in larger distances from the target at lower pressures, in the formation of structured electron energy distributions with a substantial contribution from a high-energy group of electrons, which is responsible for enhanced gas ionization and relatively high values observed for the difference between the plasma and the floating potential.

Abnormal residual stress state in ZnO films synthesized by planar magnetron sputtering system with two facing targets

The structure and residual stresses of ZnO films synthesized by a planar magnetron sputtering system with two facing targets were investigated by X-ray diffraction. ZnO films were deposited onto a sheet of Corning 7059 glass. The X-ray diffraction pattern shows that the film has high 00·1 orientation. Residual strains were measured on various diffraction lines that appear at special angles ψ from the surface normal. The strains taken from positive and negative ψ differed from each other. This behavior is deduced from the existence of a shear stress component in a cross-section of the film. The magnitude of the shear stress increased with increasing current density of the Zn target as well as with decreasing argon gas pressure.

Structural study of metastable (GaAs) 1− X(Ge 2) X thin films grown by RF magnetron sputtering

Epitaxial metastable (GaAs) 1− X (Ge 2) X thin films have been grown on GaAs(1 0 0) in a RF planar magnetron sputtering system (MS), without As overpressure, throughout most of the full compositional X range. The structural and compositional properties were investigated by high resolution X-ray diffraction (HRXRD) and secondary ion mass spectrometry (SIMS). The SIMS depth profiles demonstrate good homogeneity of Ge concentration for all the samples. HRXRD measurements show that the lattice constant dependence on the concentration X does not obey Vegard's law and that a transition between zinc-blende and diamond crystal structures occurs at X≈0.35

Effect of external magnetic field on c-axis orientation and residual stress in AlN films

Crystal orientation and residual stress development in AlN films on borosilicate glass (the thermal expansion coefficient of which is nearly equal to that of AlN) substrate were investigated by atomic force microscopy (AFM) observation and X-ray diffraction method. The AlN films were prepared by a planar magnetron sputtering system with two opposite targets under the condition of constant nitrogen gas pressure, constant substrate temperature, various deposition time and various external magnetic field (EM) between 63 and 128 gauss. We obtain the following results: (1) the size of crystal grains was large and the value of FWHM of 00·2 diffraction line was small at large EM; (2) the c-axis orientation was good for all films; (3) the large tensile residual stresses were obtained at large EM and decreased with decreasing the EM because of ion peening.

Processing of continuously reinforced Ti-alloy metal matrix composites (MMC) by magnetron sputtering

The present work deals with a novel vapor synthesis route, the matrix-coated fiber process, for producing SiC fiber reinforced Ti–6Al–4V and Ti 3Al–Nb ‘orthorhombic’ titanium aluminide composites. In this process, the matrix alloys were directly deposited on SiC fibers by magnetron sputtering. The matrix deposition was conducted both as a batch process, wherein short-length fibers were coated with the matrix material using a planar magnetron sputtering system, as well as a continuous process, in which the matrix was deposited on continuous SiC fibers using a reel-to-reel hollow-cathode magnetron sputtering system. The matrix-coated fibers were consolidated to produce unidirectionally reinforced composite panels. Unreinforced matrix alloy samples were also fabricated using the same sputtering and consolidation conditions. Following heat treatments, the microstructural evolution in these materials were studied. Tensile tests at room temperature were also conducted on matrix and composite specimens. The results indicated that PVD foils and fiber coatings can be heat-treated to obtain microstructures similar to those obtained via conventional processing approaches. Further, the room-temperature tensile properties of PVD foils are comparable to conventionally rolled foils or sheets.

Magnetron sputtering system stabilisation for high rate deposition of AlN films

The stabilisation of a planar magnetron sputtering system for reactive sputtering of AlN in a gaseous mixture of Ar and highly active NH 3 was examined. The helical instability in the cathode plasma sheath was observed and methods for its damping were proposed. It was found that the deposition of c-axis oriented AlN films at high deposition rates in the range 0.5–3.0 m/h is possible, when the helical instability in the magnetron system is damped.

Thermal power at a substrate during ZnO:Al thin film deposition in a planar magnetron sputtering system

In a balanced magnetron sputtering system the thermal power at a substrate has been determined from the temperature change of the substrate when the plasma is switched on. Using the temperature as a function of the potential of a probe, the calorimeter has been calibrated absolutely. A heat input equivalent of about 10 eV per electron has been determined for a dc discharge. The results for the total thermal power at the substrate are compared with values published by other groups for similar discharge systems. The contributions of different kinds of particles are discussed. For the dc discharge at a discharge power of 50 W and a pressure of 0.8 Pa, a thermal power of 15.6 mW cm−2 has been found which is mainly produced by particles other than the plasma ions. It can be concluded from the increase of the thermal power with decreasing pressure that bombardment by particles originating from the target is the main source of the substrate heating. In an rf discharge the ion energy is two times and the flux density is nearly three times higher than in a dc discharge. Here the dependence of the thermal power on pressure is only weak and mainly the plasma ions transport the power to the substrate.