Magnetron Sputtering Deposition Technique Research Articles

Irradiation effects of 6 MeV electron on electrical properties of Al/Al2O3/n-Si MOS capacitors

The influence of 6MeV electron irradiation on the electrical properties of Al/Al2O3/n-Si metal–oxide–semiconductor (MOS) capacitors has been investigated. Using rf magnetron sputtering deposition technique, Al/Al2O3/n-Si MOS capacitors were fabricated and such twelve capacitors were divided into four groups. The first group of MOS capacitors was not irradiated with 6MeV electrons and treated as virgin. The second group, third group and fourth group of MOS capacitors were irradiated with 6MeV electrons at 10kGy, 20kGy, and 30kGy doses, respectively, keeping the dose rate ∼1kGy/min. The variations in crystallinity of the virgin and irradiated MOS capacitors have been compared from GIXRD (Grazing Incidence X-ray Diffraction) spectra. Thickness and in-depth elemental distributions of individual layers were performed using Secondary Ion Mass Spectrometry (SIMS). The device parameters like flat band voltage (VFB) and interface trap density (Dit) of virgin and irradiated MOS capacitors have been calculated from C vs V and G/ω vs V curve, respectively. The electrical properties of the capacitors were investigated from the tan δ vs V graph. The device parameters were estimated using C–V and G/ω–V measurements. Poole–Frenkel coefficient (βPF) of the MOS capacitors was determined from leakage current (I)–voltage (V) measurement. The leakage current mechanism was proposed from the βPF value.

Structural Characterization of Sputter-Deposited 304 Stainless Steel+10 wt pct Al Coatings

An SS304 + 10 wt pct Al (with a nominal composition of Fe-18Cr-8Ni-10Al by wt pct and corresponding to Fe-17Cr-6Ni-17Al by at. pct) coating was deposited on a 304-type austenitic stainless steel (Fe-18Cr-8Ni by wt pct) substrate by the magnetron sputter-deposition technique using two targets: 304-type stainless steel (SS304) and Al. The as-deposited coatings were characterized by X-ray diffraction, transmission electron microscopy, and three-dimensional (3-D) atom probe techniques. The coating consists of columnar grains with α ferrite with the body-centered cubic (bcc) (A2) structure and precipitates with a B2 structure. It also has a deposition-induced layered structure with two alternative layers (of 3.2 nm wavelength): one rich in Fe and Cr, and the other enriched with Al and Ni. The layer with high Ni and Al contents has a B2 structure. Direct confirmation of the presence of B2 phase in the coating was obtained by electron diffraction and 3-D atom probe techniques.

Time-dependent mechanical behavior of phase-separated ZrCuTiTa thin films under nanoindentation

A series of Ta-modified amorphous ZrCuTi thin films were produced by magnetron sputter deposition techniques. Microstructural examination using transmission electron microscopy indicated that the Ta addition induced phase separation and resulted in two-phase glass structures. The composition and morphology (such as density, size, and volume fraction) of the second-phase structure were characterized. The mechanical properties, including modulus and hardness, were measured using a nanoindentation method and compared with the predictions from theoretical models. Nanoindentation creep experiments were also conducted to evaluate the viscoelastic response of the two-phase glasses. The characteristic relaxation time was found to be a function of the glass transition temperature. Its physical significance was discussed.

Design, production, and reverse engineering of two-octave antireflection coatings

We deal with design and production of optimal two-component antireflection (AR) coatings for an ultra broadband spectral range from 450 nm to 1800 nm. We demonstrate the whole design-production chain including design selection, choosing monitoring technique, coating production, and reverse engineering of the deposited coatings. At each step of this chain we provide thorough analysis on the basis of theoretical results and adequate computational manufacturing experiments. In order to produce the designed AR coatings we use magnetron sputtering deposition technique and accurate time monitoring.

X-ray diffraction and surface acoustic wave analysis of BST/Pt/TiO2/SiO2/Si thin films

High dielectric constant and electrostriction property of (Ba, Sr)Ti03 (BST) thin films result in an increasing interest for dielectric devices and microwave acoustic resonator. Barium strontium titanate (Ba0.645Sr0.355TiO3) films of about 300 nm thickness are grown on Pt(111)/TiO2/SiO2/Si(001) substrates by rf magnetron sputtering deposition techniques. X-ray diffraction is applied for the microstructural characterization. The BST films exhibit a cubic perovskite structure with a dense and smooth surface. A laser acoustic waves (LA-waves) technique is used to generate surface acoustic waves (SAW) propagating in the BST films. Young’s modulus E and the Poisson ratio ν of TiO2, Pt and BST films in different propagation directions are derived from the measured dispersion curves. Estimation of BST elastics constants are served in SAW studies. Impact of stratification process on SAW, propagating along [100] and [110] directions of silicon substrate, has been interpreted on the basis of ordinary differential equation (ODE) and stiffness matrix method (SMM). A good agreement is observed between experimental and calculated dispersion curves. The performed calculations are strongly related to the implemented crystallographic data of each layer. Dispersion curves are found to be sensitive to the SAW propagation direction and the stratification process for the explored frequency ranges 50−250 MHz, even though it corresponds to a wave length clearly higher than the whole films thickness.

Characterization of the surface topography and nano-hardness of Cu/Ni multilayer structures

Abstract This article describes the results of a study of Cu/Ni multilayer coatings applied on a monocrystalline Si(100) silicon substrate by the deposition magnetron sputtering technique. Composed of 100 bilayers each, the multilayers were differentiated by the Ni sublayer thickness (1.2 to 3 nm), while maintaining the constant Cu sublayer thickness (2 nm). The multilayer coatings were characterized by assessing their surface topography using atomic force microscopy and their mechanical properties with nano-hardness measurements by the Berkovich method. The tests showed that the hardness of multilayers was substantially influenced by the thickness ratio of Cu and Ni sublayers and by surface roughness. The highest hardness and, at the same time, the lowest roughness was exhibited by a multilayer structure with a Cu-to-Ni sublayer thickness ratio of 2:1.5.

Nitrogen [N]-incorporated ZnO piezoelectric thin films and their application for ultra-small film bulk acoustic wave resonator device fabrication

Nitrogen [N]-incorporated ZnO films with columnar grains of a preferred c-axis orientation were deposited on p-Si (100) wafers, using an RF magnetron sputter deposition technique. For the N incorporation into the ZnO films, an N2O gas was used as a doping source and also various process conditions such as N2O gas fraction and RF power were applied. Besides, some of the ZnO films were treated with the post annealing process. And then, the micro-structural characteristics of the N-incorporated ZnO films were investigated by a scanning electron microscope, an X-ray diffractometer, and an atomic force microscope techniques. Finally, employing the N-incorporated ZnO films, the solidly mounted resonator-type film bulk acoustic wave resonator devices were fabricated and their resonance characteristics were extracted. As a result, an excellent return loss (S11) of− 63 dB was observed at∼ 0.6 GHz, better than ever reported.

Sputtering and Pulsed Laser Deposition for Near- and Mid-Infrared Applications: A Comparative Study of Ge25Sb10S65 and Ge25Sb10Se65 Amorphous Thin Films

The deposition of Ge25Sb10S65 and Ge25Sb10Se65 amorphous chalcogenide thin films was performed by radio-frequency magnetron sputtering and pulsed laser deposition technique. The deposited layers were characterized by studying their morphology, topography, chemical composition, structure, and optical functions permitting a direct comparison of two deposition methods for obtaining attractive amorphous chalcogenide films. Reactive ion etching was then used to pattern rib/ridge waveguides in sulfide and selenide films with low surface roughness, vertical sidewalls, and reasonable etching rate. Optical losses of fabricated waveguides were measured at 1550 nm with values better than 1 dB/cm obtained for sulfide/selenide films deposited by both techniques.

Infrared suppression by hybrid EUV multilayer—IR etalon structures

We have developed a multilayer mirror for extreme UV (EUV) radiation (13.5 nm), which has near-zero reflectance for IR line radiation (10.6 μm). The EUV reflecting multilayer is based on alternating B4C and Si layers. Substantial transparency of these materials with respect to the IR radiation allowed the integration of the multilayer coating in a resonant quarter-wave structure for 10.6 μm. Samples were manufactured using magnetron sputtering deposition technique and demonstrated suppression of the IR radiation by up to 3 orders of magnitude. The EUV peak reflectance amounts 45% at 13.5 nm, with a bandwidth at FWHM being 0.284 nm. Therefore such a mirror could replace conventional multilayer mirrors to suppress undesired spectral components in monochromatic imaging applications, including EUV photolithography.

Improvement of the fretting damage resistance of Ti-811 alloy by Cu/Ni multilayer films

The Cu/Ni multilayer films were prepared on the titanium alloy surface by ion-assisted magnetron sputtering deposition (IAD) technique. The Cu/Ni multilayer films could significantly improve the resistance of fretting wear and fretting fatigue (FF) of Ti-811 alloy at room temperature. The FF resistance of the titanium alloy substrate did not increase monotonically with increase in the modulation period thickness of the Cu/Ni multilayer films. The Cu/Ni multilayer films with modulation period thickness of 200 nm had the highest FF resistance among the prepared Cu/Ni multilayer films for its comprehensive properties with high toughness, high strength and good lubricating action.

Direct current magnetron sputter-deposited ZnO thin films

Zinc oxide (ZnO) is a very promising electronic material for emerging transparent large-area electronic applications including thin-film sensors, transistors and solar cells. We fabricated ZnO thin films by employing direct current (DC) magnetron sputtering deposition technique. ZnO films with different thicknesses ranging from 150nm to 750nm were deposited on glass substrates. The deposition pressure and the substrate temperature were varied from 12mTorr to 25mTorr, and from room temperature to 450°C, respectively. The influence of the film thickness, deposition pressure and the substrate temperature on structural and optical properties of the ZnO films was investigated using atomic force microscopy (AFM) and ultraviolet–visible (UV–Vis) spectrometer. The experimental results reveal that the film thickness, deposition pressure and the substrate temperature play significant role in the structural formation and the optical properties of the deposited ZnO thin films.

Modified TiAlN coatings prepared by d.c. pulsed magnetron sputtering

Coatings like TiN or TiAlN are well established as hard and wear resistant tool coatings. These coatings often are prepared by PVD techniques like arc evaporation or d.c. magnetron sputtering. Typical micro hardness values of such hard coatings are in the range of 30 GPa. Compared to d.c. magnetron sputtering processes the pulsed magnetron sputter deposition technique could be shown as a clear advancement. Furthermore pure TiAlN hard coatings as well as TiAlN coatings modified by addition of elements like Si and Cr were prepared in order to improve the coating properties using the pulsed magnetron sputter technique in a batch coater equipped with 4 targets. Coatings prepared with the pulsed sputter process showed both high hardness and high wear resistance. The application potential of pulsed sputtered TiAlN coatings is demonstrated by turning test results of coated cemented carbide cutting inserts. Beside hardness and wear, other properties like adhesion or high temperature stability were determined. Cross sectional SEM images revealed the growth structure in dependence of the applied substrate bias and of the added elements. The chemical composition of the coatings was investigated by electron microprobe analysis and the phase and crystal size were determined by X-ray diffraction. Using the pulsed magnetron sputter process the coating properties, especially the hardness and the morphology, could be significantly improved. With indentation hardness values in the range of 40 GPa the region of super hard materials could be reached.

Low friction CrN/TiN multilayer coatings prepared by a hybrid high power impulse magnetron sputtering/DC magnetron sputtering deposition technique

High power impulse magnetron sputtering (HIPIMS) has gained increasing scientific and industrial attention as it allows high plasma densities without the drawback of droplet formation. Recently, we showed that by a combination of HIPIMS with dc magnetron sputtering the properties of the coatings are comparable to those prepared solely with HIPIMS, but with the advantage of increased deposition rate. Here, we show that for CrN HIPIMS/TiN DCMS multilayered coatings the friction coefficient µ decreases from 0.7 to 0.35 (with an almost constant hardness H around 25 GPa, and modulus of indentation around 375 GPa) when decreasing the bilayer period λ from 7.8 to 6.4 nm, while keeping the CrN HIPIMS layer thickness constant at 3.2 nm. A further reduction of the friction coefficient at room temperature dry-sliding testing to ∼ 0.25 or 0.05 is obtained when an additional HIPIMS cathode equipped with a Cr or Ti target material, respectively, is added to the process. Contact angle measurements of distilled water drops on as deposited film surfaces were carried out to investigate their wettability. The measurements show, that with increasing contact angle from 70° to 90°, for the individual coatings prepared, also their friction coefficient increases from ∼ 0.05 to ∼ 0.8. The depositions of all coatings were achieved with two- and threefold substrate rotation, which meet the industrial requirements of uniform deposition on complex shaped specimens.

Fabrication of Si nanocrystals in an amorphous SiC matrix by magnetron sputtering

Si nanocrystals embedded in a wide bandgap material have been of interest for various electronic devices, including third-generation solar cells with efficiency values exceeding theoretical limits. In this work, Si-rich amorphous SiC layers with different Si contents were fabricated by the RF magnetron sputtering deposition technique. Si nanocrystal formation was induced by a high-temperature annealing process in a series of samples with different Si contents controlled by the DC power applied to the Si target during the sputtering. Nanocrystal formation was monitored to understand the basic kinetics as a function of process parameters, such as DC power and annealing temperature. In the SiC films containing excess Si, nanocrystal formation was clearly identified by Raman spectroscopy and high-resolution Transmission Electron Microscopy (TEM). Si nanocrystals with a mean size of 2 nm were imaged by TEM in the samples annealed at 1100 °C. The presence of Si–Si bonds was also detected by XPS through a series of experiments, including depth profiling of the chemical bonds of O, Si and C as a function of depth from the surface. Infrared spectroscopy was employed to study the stoichiometry of the SiC matrix with or without nanocrystals.

Room-Temperature Synthesis of Single-Crystalline Anatase TiO2 Nanowires

Single-crystalline anatase TiO2 nanowires have been synthesized using a novel, room-temperature method involving the use of seed particles and a radio frequency magnetron sputter deposition technique. Also, the growth time required was less than 60 min. Transmission electron microscopy and X-ray absorption near-edge structure analyses show that the obtained nanowires are single-crystalline anatase TiO2. Cathodoluminescence spectroscopy spectrum shows that the nanowires’ band-to-band emission exhibits a blue shift from to 3.20 (387) to 3.46 eV (358 nm). Conventional vapor−liquid−solid and vapor−solid−solid growth modes are not applicable to explain the growth of the obtained single-crystalline anatase TiO2 nanowires at room-temperature. A folded-growth mode is therefore suggested.

Bonelike Apatite Formation Utilizing Carbon Nanotubes as Template

Template-induced hydroxyapatite (HA) has broad prospects in the applied fields of regenerative medicine and bone repair. HA thin coatings have been deposited on vertically aligned multiwalled carbon nanotubes (CNTs) via the high-temperature radio-frequency (rf) magnetron sputtering deposition technique. Simulated body fluid (SBF) solution has been used to soak and incubate the HA/CNTs nanocomposites at 37 degrees C. SEM, EDS, XRD, and FTIR characterizations revealed bonelike apatite formation on top of HA/CNTs composites. Coating HA material on well-aligned CNT-template provides a way of combining the superior mechanical properties and chemical stability of the CNTs with the excellent biochemical properties of HA.

Growth and characterizations of ZnO nanorod/film structures on copper coated Si substrates

ZnO deposits were obtained on electroless copper coated Si substrates using a conventional RF magnetron sputter deposition technique at room temperature. The deposition pressure was varied from 6.67Pa to 0.667Pa. The RF powers were from 100 to 200W and the electrode distance was fixed at 5cm. The ZnO deposition time was varied from 1 to 30min. The deposits consist of ZnO nanorods and a ZnO film, with the roots of the nanorods embedded in the film. The growth of the nanorods far exceeds the growth of the film in the beginning of the deposition process. The nanorod lengthening rate then slows down and becomes lower than the film growth rate. Effects of sputter deposition parameters on the growth of ZnO nanorods/film structures were also investigated.

Kinetic modeling of the total oxidation of propane over anatase and vanadia sputter deposited catalysts

Using an innovative magnetron sputter deposition technique, a set of titania (anatase), vanadia and vanadia–titania (anatase) based catalysts on porous SiO2 and non-porous SiO2–ZrO2 supports is prepared. These catalysts are tested for propane total oxidation at atmospheric pressure, a constant oxygen inlet partial pressure of 28.4kPa and temperatures from 733 to 773K. The inlet ratio of oxygen and propane is varied between 7.7 and 85.3molmol−1. A longer TiOx sputter deposition time has a beneficial effect on the propane total oxidation turnover frequency (TOF). Furthermore, the use of a porous support results in higher TOF. Starting from eleven possible rate equations, the one corresponding to a Mars–van Krevelen (MVK) mechanism, involving one active site in the reduction and reoxidation step, is globally the most significant. A pronounced compensation effect is observed for the rate coefficients of the reoxidation and reduction steps.

Superlow friction behavior of Si-doped hydrogenated amorphous carbon film in water environment

Si-doped hydrogenated amorphous carbon (a-C:H:Si) film was prepared using hybrid radio frequency plasma-enhanced chemical vapor deposition (R.F. PECVD) and non-balanced magnetron sputtering deposition technique. The microstructure of the film was characterized by means of Raman spectrometry, X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD), while its friction behavior in water environment was investigated using a ball-on-disc tribometer. Results show that the a-C:H:Si film has typical diamond-like characteristics, and Si doped with a relative atomic concentration of about 3.9% in the film mainly exists in the form of Si, SiC, and SiO 2, while it shows a superlow friction coefficient of about 0.005 in water environment when sliding against Si 3N 4 ball. The superlow friction behavior of the hybrid diamond-like-carbon (DLC) film could be attributed to the formation of a tribochemical reaction film and boundary lubrication layer mainly consisting of colloidal silica generated from tribochemical reactions between silicides and water molecules.

Tribological behaviour of Ti containing nanocomposite DLC films under milli-Newton load range

In recent days nanocomposite films deposited by various CVD or PVD techniques are receiving intense attention because of their high hardness or high toughness. These films are considered to be potential layers for tribological applications. The present investigation is undertaken to evaluate the tribological behaviour of a nanocomposite Ti containing diamond like carbon film in the load range of milli-Newtons keeping in view the possible application in micro mechanical assemblies (MMA). Towards that purpose, films containing various Ti concentrations are deposited with the help of unbalanced magnetron sputter deposition technique. The tribological properties of these films are evaluated at 500 mN applied load. It is noted that the film containing 46 at % Ti has the maximum hardness in the order of 15.5 GPa and also very high plastic deformation. This film also shows a very low friction coefficient and wear rate.