Magnetron Sputtering Deposition Technique Research Articles

Infrared metamaterial by RF magnetron sputtered ZnO/Al:ZnO multilayers

Hyperbolic metamaterials create artificial anisotropy using metallic wires suspended in dielectric media or alternating layers of a metal and dielectric (Type I or Type II). In this study we fabricated ZnO/Al:ZnO (AZO) multilayers by the RF magnetron sputtering deposition technique. Our fabricated multilayers satisfy the requirements for a type II hyperbolic metamaterial. The optical response of individual AZO and ZnO films, as well as the multilayered film were investigated via UV-vis-IR transmittance and spectroscopic ellipsometry. The optical response of the multilayered system is calculated using the nonlocal-corrected Effective Medium Approximation (EMA). The spectroscopic ellipsometry data of the multilayered system was modeled using a uniaxial material model and EMA model. Both theoretical and experimental studies validate the fabricated multilayers undergo a hyperbolic transition at a wavelength of 2.2 μm. To our knowledge this is the first AZO/ZnO type II hyperbolic metamaterial system fabricated by magnetron sputtering deposition method.

Multifunctional surface designed by nanocomposite coating of polytetrafluoroethylene and TiO2 photocatalyst: self-cleaning and superhydrophobicity

Multifunctional surface, having both a superhydrophobic property and a photocatalytic self-cleaning property, was designed through a nanocomposite coating of polytetrafluoroethylene (PTFE) and TiO2 photocatalyst onto a flat quartz glass with a precise structural controlling by applying a radio frequency magnetron sputtering deposition technique. Systematic water contact angle measurements were carried out in relation to the controlling of the surface structure such as size, height and others. Surface wettability gradually changes from Wenzel state to Cassie-Baxter state by controlling of the surface structure, resulting in a well water repellent behavior. Under irradiation of UV light, nanocomposite coating with a desired surface structure and composition realized an adequate photocatalytic self-cleaning property for keeping a clean surface and inducing unique surface wettability changes.

A comparative study of copper thin films deposited using magnetron sputtering and supercritical fluid deposition techniques

A comparison of crystallinity, microstructure, surface morphology and electrical conductivity is proposed for the deposition of copper films, using supercritical fluid chemical deposition (SFCD) and RF magnetron sputtering techniques. Both preparation methods yield nanocrystalline Cu films (<100nm) but SFCD gives access to a higher crystallinity for the same AlN substrate temperature during the deposit. Based on the film characteristics, a comparison of the evolution of electrical properties is done for RF magnetron sputtered copper films and SFCD ones with H2 as reducing agent. Uniform strain values are significantly reduced when SFCD technique is used and crystallinity is highly increased leading to lower resistivity values for a same crystallite size. This study demonstrates the viability of the SFCD technique to produce high quality nanostructured copper thin films with low resistivity values.

Preferential orientation growth of ITO thin film on quartz substrate with ZnO buffer layer by magnetron sputtering technique

In order to improve the photoelectric transformation efficiency of thin-film solar cells, one plausible method was to improve the transparent conductive oxides (TCO) material property. In-doped tin oxide (ITO) was an important TCO material which was used as a front contact layer in thin-film solar cell. Using magnetron sputtering deposition technique, we prepared preferential orientation ITO thin films on quartz substrate. XRD and SEM measurements were used to characterize the crystalline structure and morphology of ITO thin films. The key step was adding a ZnO thin film buffer layer before ITO deposition. ZnO thin film buffer layer increases the nucleation center numbers and results in the (222) preferential orientation growth of ITO thin films.

Properties of Gadolinium-doped Ceria (GDC) Films Deposited by Reactive Magnetron Sputtering Processes

Reactive magnetron sputtering deposition technique was used for formation of gadolinium doped ceria oxide (GDC) thin films 5- 10µm. Material characteristics and chemical compositions of GDC films were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and 3D profilometry. In order to optimize the deposition of GDC to obtain high electrochemical performance of the cells, the influence of film thickness is studied. The GDC thin films were deposited on porous NiO–GDC (nickel oxide–Gadolinium stabilized ceria), the pre-sintered anode green tape were coated with a GDC electrolyte film by reactive magnetron sputtering using PEM (Plasma Emission Monitoring). An Alcatel SCM650 sputtering chamber was used for synthesizing the dense GDC layers. A Ce-Gd metallic target (90-10% at) was powered by a pinnacle + pulsed current generator from Advanced Energy. The structural, microstructural and morphological features of the half-cells were determined by XRD, SEM and 3D profilometry as deposited and after different annealing treatments. The obtained half-cell, 28 mm of diameter, anode supported solid oxide fuel cell, the porous and density of Ni-GDC10 composite anodes have been elaborated by tape casting method. The chosen ceramic powders in suspension were prepared with the mass ratio of 65:35 for NiO to GDC10. The microstructural morphological /porosity/surface features of the half-cell were analyzed by Scanning Electron Microscopy (SEM), XRD and 3D profilometry before and after different annealing treatment. Pycnometry and porosimetry techniques were primarily used to determine pore size and pore volume by equation Washburn and Ideal gas law-method. Finally, the EIS (Electrochemical Impedance Spectroscopy) measurements were done on Ni-GDC10/GDC10 half-cells under 60 sccm nitrogen by the means of a Solartron SI 1260 impedance / gain analyser from 20 MHz to 0.1 Hz with 11 points per decade.

Properties of Gadolinium-doped Ceria (GDC) Films Deposited by Reactive Magnetron Sputtering Processes

Reactive magnetron sputtering deposition technique was used for formation of gadolinium doped ceria oxide (GDC) thin films 5- 10µm. Material characteristics and chemical compositions of GDC films were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). In order to optimize the deposition of GDC to obtain high electrochemical performance of the cells, the influence of film thickness is studied. The GDC thin films were deposited on porous NiO–GDC (nickel oxide–Gadolinium stabilized ceria), the pre-sintered anode green tape were coated with a GDC electrolyte film by reactive magnetron sputtering using PEM (Plasma Emission Monitoring). An Alcatel SCM650 sputtering chamber was used for synthesizing the dense GDC layers. A Ce-Gd metallic target (90-10% at) was powered by a pinnacle + pulsed current generator from Advanced Energy. The structural, microstructural and morphological features of the half-cells were determined by XRD and SEM as deposited and after different annealing treatments. The obtained half-cell, 28 mm of diameter, anode supported solid oxide fuel cell, the porous and density of Ni-GDC10 composite anodes have been elaborated by tape casting method. The chosen ceramic powders in suspension were prepared with the mass ratio of 65:35 for NiO to GDC10. Finally, Pycnometry and porosimetry techniques were primarily used to determine pore size and pore volume by equation Washburn and Ideal gas law-method.

Structure and morphology of magnetron sputter deposited ultrathin ZnO films on confined polymeric template

The structure and morphology of ultra-thin zinc oxide (ZnO) films with different film thicknesses on confined polymer template were studied through X-ray reflectivity (XRR) and grazing incidence small angle X-ray scattering (GISAXS). Using magnetron sputter deposition technique ZnO thin films with different film thicknesses (<10nm) were grown on confined polystyrene with ∼2Rg film thickness, where Rg∼20nm (Rg is the unperturbed radius of gyration of polystyrene, defined by Rg=0.272 √M0, and M0 is the molecular weight of polystyrene). The detailed internal structure, along the surface/interfaces and the growth direction of the system were explored in this study, which provides insight into the growth procedure of ZnO on confined polymer and reveals that a thin layer of ZnO, with very low surface and interface roughness, can be grown by DC magnetron sputtering technique, with approximately full coverage (with bulk like electron density) even in nm order of thickness, in 2–7nm range on confined polymer template, without disturbing the structure of the underneath template. The resulting ZnO-polystyrene hybrid systems show strong ZnO near band edge (NBE) and deep-level (DLE) emissions in their room temperature photoluminescence spectra, where the contribution of DLE gets relatively stronger with decreasing ZnO film thickness, indicating a significant enhancement of surface defects because of the greater surface to volume ratio in thinner films.

Deposition of ZnO thin films by RF&DC magnetron sputtering on silicon and porous-silicon substrates for pyroelectric applications

In this study, the temperature response of ZnO thin film is investigated in an attempt to enhance its pyroelectric performance. The film is formed on PS and Si substrates utilizing RF&DC magnetron sputtering deposition technique. The outcome of study reveals a pyroelectric coefficient observed from ZnO film on PS which is 40 times higher than that on Si and a pyroelectric voltage as high as 2.4V due to PS's profound effect on film formation, large surface to volume area and low thermal conductivity. Thus, this study can lead the way to a robust, reliable and more efficient pyroelectric operation of ZnO with employment of PS structure.

Glancing angle deposition of SiO2 thin films using a novel collimated magnetron sputtering technique

A novel deposition flux collimation technique has been explored in combination with glancing angle deposition geometry in radio frequency magnetron sputtering deposition technique with a motive to tailor the refractive index of silicon di-oxide thin film. In this technique, a collimating plate has been placed in parallel to the substrate at variable substrate to collimator distances (DSC=4mm, 6mm and 9mm) and the effect of DSC on various properties of the deposited film at different spatial locations on the substrate has been investigated. The use of such collimator was found to be highly effective in reducing the refractive index of the deposited film. A lowest refractive index of ~1.31 @ 550nm of SiO2 was achieved by using this novel collimation technique in combination with glancing angle deposition geometry which is not possible by glancing angle deposition geometry alone in the framework of non-directional deposition flux in magnetron sputtering technique. Variable angle spectroscopic ellipsometry (VASE) has been employed to accurately determine thickness and refractive index of the deposited films at various spatial locations of the sample. Ellipsometry data fitting model at different spatial locations has been verified by simulating the transmission spectrum based on the layer structure model obtained from ellipsometry modeling and then comparing it with that of the experimentally measured transmission spectra. For a given DSC an optimum location on the substrate surface was obtained to exhibit lowest refractive index. FTIR measurement showed no significant difference in bonding behavior of SiO among different representative spots of the deposited SiO2 samples. AFM measurement on various spatial locations indicates a possible strong correlation between variation of refractive index and the grain size which is again affected by the degree of collimation and ad atom kinetic energy at various spatial locations.

Structural and optical properties of Al/ZnO thin films deposited by radio frequency sputtering

The effects of annealing temperature and variation of sample thickness on the structural and optical properties of zinc oxide thin films with aluminium contact (Al/ZnO) have been investigated. The study involved the synthesis of a bilayer thin film of Al/ZnO with varied thicknesses on a glass slide substrate by using radio frequency magnetron sputtering deposition technique. 99.99% pure ZnO and aluminium were used as the sputtering target. The films were then annealed in vacuum at annealing temperatures of 200 °C and 400 °C. The structural and optical properties of Al/ZnO thin films grown were characterized by x-ray diffraction (XRD) and optical measurements respectively. The results obtained from the XRD patterns showed that Al/ZnO films (both as-deposited and annealed), exhibits a crystalline structure with (002) preferred orientation. The peak intensity of the preferred plane increases as the annealing temperature increases. The optical studies of the Al/ZnO films showed a maximum value of transmittance ranging from 82% to 91% depending on the condition of the films. A decrease in transmittance as the thickness of the films increases was observed. The transmittance also increased with increasing annealing temperature. The energy gaps (Eg) were determined from the transmittance data and found to be in the range 3.73–3.83 eV. The results obtained from the experiment also show that the optical band gap increases as the thickness and annealing temperature increase.

The effect of the thickness of tunneling layer on the memory properties of (Cu2O)0.5(Al2O3)0.5 high-k composite charge-trapping memory devices

The charge-trapping memory devices namely Pt/Al2O3/(Al2O[Formula: see text](Cu2O)[Formula: see text]/SiO2/[Formula: see text]-Si with 2, 3 and 4 nm SiO2 tunneling layers were fabricated by using RF magnetron sputtering and atomic layer deposition techniques. At an applied voltage of ±11 V, the memory windows in the C–V curves of the memory devices with 2, 3 and 4 nm SiO2 tunneling layers were about 4.18, 9.91 and 11.33 V, respectively. The anomaly in memory properties among the three memory devices was ascribed to the different back tunneling probabilities of trapped electrons in the charge-trapping dielectric (Al2O[Formula: see text](Cu2O)[Formula: see text] due to the different thicknesses of SiO2 tunneling layer.

The Characteristic Parameters of Ni/n-6H-SiC Devices Over a Wide Measurement Temperature Range

Ni/n-type 6H-SiC/Ni Schottky barrier diodes (SBDs) have been prepared by the DC magnetron sputtering deposition technique. Their current-voltage characteristics (I-V) have been measured in the measurement temperature range of 40-400 K with steps of 20 K under dark conditions. The barrier height (BH) values from the temperature-dependent forward and reverse bias I-V characteristics by different methods coincide with each other which indicates the elimination of the polarity between the Si and C ions. The ideality factor value remains almost unchanged in the 160-400 K range, and below 160 K, it has the values of 1.57 at 140 K, and 3.82 at 60 K. The BH has the values of 0.79 eV at 400 K, and 0.71 eV at 300 K. The decrease in the BH is due to the fact that the current will preferentially flow through the lowest BH with decreasing temperature due to barrier inhomogeneity. The value of 0.71 eV at 300 K is in close agreement with the values of 0.65 and 0.83 eV reported from the forward bias I-V characteristics for the Ni /n-type 6H-SiC in the literature. Thus, it has been concluded that the reduced barrier devices are promising for applications in devices operating at cryogenic temperatures as infrared detectors, sensors in thermal imaging and small signal zero-bias rectifiers and microwave mixers.

Low friction coefficient coatings Ni-Cr by magnetron sputtering, DC

Magnetron Sputter Deposition technique with DC was used for the deposition of Ni-Cr coatings on AISI 316 SS like substrate. The cathode with a nominal composition Ni-22 at% Cr was prepared by Mechanical Alloying (MA) technique, with a maximum milling time of 16 hours and, with a high energy SPEX 8000 mill. The coatings were made under Argon atmosphere at room temperature with a power of 100 W at different times of growth. Chemical composition, microstructure, topography, nanohardness and wear of the coatings were evaluated using the techniques of microanalysis by energy dispersive X-ray analyzer (EDAX), X-Ray Diffraction (XRD), Atomic Force Microscopy (AFM), Nano-indentation and pin-on-Disk, respectively. After milling, was not detected contamination in the mixtures. XRD analysis revealed that the microstructure of the Ni-Cr alloy was maintained in the coatings with respect to MA powders, with some degree of recrystallization. Nanohardness values were in the order of 8.8 GPa with a Young’s modulus of 195 GPa. The adhesion of the films was evaluated according to their resistance to fracture when these were indented at different loads using Vickers microhardness. The wear test results showed a decrease in the friction coefficient with respect to the increase of thickness’ films, getting a minimum value of 0.08 with a thickness of 1 μm and which correspond with the maximum growing time.

Corrosion resistance analysis of aluminium-doped zinc oxide layers deposited by pulsed magnetron sputtering

In this paper an exhaustive analysis is performed on the electrochemical corrosion resistance of Al-doped ZnO (AZO) layers deposited on silicon wafers by a DC pulsed magnetron sputtering deposition technique to test layer durability. Pulse frequency of the sputtering source was varied and a detailed study of the electrochemical corrosion response of samples in the presence of a corrosive chloride media (NaCl 0.06M) was carried out. Electrochemical impedance spectroscopy measurements were performed after reaching a stable value of the open circuit at 2h, 192h and 480h intervals. Correlation of the corrosion resistance properties with the morphology, and the optical and electrical properties was tested. AZO layers with transmission values higher than 84% and resistivity of 6.54×10−4Ωcm for a deposition process pressure of 3×10−1Pa, a sputtering power of 2kW, a pulse frequency of 100kHz, with optimum corrosion resistance properties, were obtained.

Effect of 750 keV Argon ion irradiation on nc ZnO[sbnd]SiOx thin films

Nanocomposite (nc) ZnOSiOx thin films were grown using rf magnetron sputter deposition technique and post-deposition annealing at 750°C. These films were irradiated with 750keV Argon ions at fluences in the range from 1×1015 to 1×1017ions/cm2, using Low Energy Ion Beam Facility (LEIBF) at IUAC. X-ray diffraction (XRD) patterns of the as-deposited irradiated films show decrease in intensity of ZnO peaks relative to pristine film. Fourier transform infrared (FT-IR) spectroscopy measurements of the as-deposited irradiated films indicate the breakage of ZnO, ZnOSi and SiOSi bonds in them, which is substantiated by FT-IR measurements of 750°C annealed films that were irradiated at a fluence of 1016ions/cm2. Photoluminescence (PL) measurements show drastic decrease of visible PL emission from as-deposited irradiated films. Current−Voltage (I–V) measurements show decrease in surface resistance of irradiated films by three orders of magnitude. The results suggest that 750keV argon ion irradiation of nc ZnO−SiOx films has resulted in the formation of non-radiative defects in ZnO phase and damage in SiOx, and amorphization in Zinc silicate phase. These results are explained on the basis of the dominant energy loss mechanism of low energy ions in materials.

Microstructure and Properties of AlSn20 Coating Deposited via Magnetron Sputtering

In view of the present reality of sputtered plating bearings imported in our country, unbalanced magnetron sputtering deposition techniques was used to fabricate AlSn20 anti-friction coating on aluminum bearing alloy. Microstructure characterization of the coating was performed by SEM. Micro-hardness testing of Coating were measured with a Vickers indenter. Adhesion testing was carried out with a scratch tester. Wear and friction tests were performed with a pin-on-disc tribometer. The results revealed that the AlSn20 anti-friction coating (bias voltage in the range of-60V~-100V) showed finer crystal, better corrosion resistance (Ecorr=-1.25V), higher hardness (up to 80HV0.025), better adhesion with substrate (up to 35N), and lower friction coefficients down to 0.15.

AlN films deposited by dc magnetron sputtering and high power impulse magnetron sputtering for SAW applications

In this work, aluminium nitride (AlN) films were deposited on silicon substrates buffered by an epitaxial AlN thin film for surface acoustic wave (SAW) applications. The films were deposited by dc magnetron sputtering (dcMS) and high power impulse magnetron sputtering (HiPIMS) deposition techniques. The structural properties of AlN films were investigated using x-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy and atomic force microscopy. In both cases of films deposited by dcMS and HiPIMS, the XRD results showed that the obtained films are oriented, with full width at half maximum rocking curves of around 1°. Raman spectroscopy revealed higher residual stress relaxation in the AlN epilayers grown by HiPIMS compared to AlN grown by dcMS, highlighted by a blue shift in the E2(high) Raman mode. The SAW measurements indicated an insertion loss of AlN-SAW devices of about 53 and 35 dB for the AlN films deposited by dcMS and HiPIMS respectively. The relation between the structural properties of AlN and the characteristics of AlN-SAW devices were correlated and discussed.

Fabrication and characterization of ferromagnetic–superconducting hybrid films grown by combined PVD techniques

This study reports micro-fabricated magnet and superconductor (permalloy/Pb82Bi18) hybrid film structures sequentially grown by magnetron sputtering and thermal deposition techniques. 300nm thick PbBi film was quench condensed on top of a patterned permalloy film. Permalloy film was sputtered and patterned to form few micrometer-wide stripes. Ferromagnetic and superconducting layers were separated by Al2O3 insulation. Transport superconducting properties, i.e. transition temperature TC(H) and second critical field HC2(T) were measured in a range of applied magnetic field between H=0 and H=7kOe for the hybrid system and a control sample with only a layer of superconducting film deposited. The HC2(T) data showed that due to the interplay between the superconducting film and the ferromagnet, superconducting (SC) and normal current paths formed on the SC film.

Development of Al oxide PVD coatings against metal dusting

Al oxide thin films were deposited on 304L stainless steel substrates to investigate their potential as protective coatings in metal dusting environments. Deposition of the films was carried out by d.c. reactive magnetron sputtering varying feeding mode of O2 flow and application of a Cr interlayer. The response to metal dusting of coated and uncoated substrates was evaluated by thermogravimetry in an atmosphere of CH4+H2+residual oxygen at 1073 K for 20 h. The results indicated that these types of coatings can effectively protect the 304L steel in these conditions. The protection was associated to good adhesion provided by the Cr interlayer and the role of the Al oxide as a barrier for diffusion. Improvement of the present coatings can be achieved within magnetron sputtering deposition techniques.

Unique Surface Properties of Nanocomposite Thin Film Photocatalysts of TiO2 and Poly(tetrafluoroethylene)

Abstract Nanocomposite thin film photocatalysts of TiO2 and poly(tetrafluoroethylene) (PTFE) were prepared by applying a radio frequency magnetron sputtering deposition technique. A superhydrophobic surface, with high transparency and photocatalytic self-cleaning property, was successfully realized by the deposition of TiO2–PTFE composite on spherical SiO2-modified quartz substrate. TiO2–PTFE composite suppressed the surface wettability changes to hydrophilic state and exhibited an adequate photocatalytic activity for the removal of oleic acid as a model contaminant of oily dirt under UV light irradiation.