Dc Planar Magnetron Sputtering Research Articles

Measurement and ab initio Investigation of Structural, Electronic, Optical, and Mechanical Properties of Sputtered Aluminum Nitride Thin Films

Aluminum Nitrides (AlN) thin films have been deposited ‎on glass substrates using DC-magnetron sputtering technique for different back pressure. The piezoelectric and related properties of highly c-axis oriented AlN films fabricated by dc planar magnetron sputtering have been calculated. Experimental results show that highly c-axis oriented AlN films can be fabricated by dc planar magnetron sputtering. X-ray powder diffraction (XRD) technique shows that AlN thin films exhibit a hexagonal structure. Vienna Ab initio Simulation Package (VASP) within the framework of density functional theory (DFT) and generalized gradient approximation (GGA) was used to investigate the structural and electronic properties of hexagonal AlN structures. The experimental lattice parameters of the as prepared thin films are found to be in good agreement with ab-initio calculated parameters. UV–Vis spectrophotometer measurements are performed to investigate the optical properties of AlN thin films. We found that the refractive index of AlN thin films exhibits values ranging between 2.1 and 2.2. Furthermore, the elastic, piezoelectric and dielectric tensors of AlN crystal are calculated using VASP. The dynamical Born effective charge tensor is reported for all atoms in the unit cell of AlN. The value of the principle component of electronic contribution to the static dielectric tensor of AlN is found to be ≈ 4.68 that is in good agreement with the experimental static dielectric constant. In addition, clamped-ion piezoelectric tensor is calculated. The diagonal components of the piezoelectric tensor are found to be e_33=1.784 C/m^2 and e_31=-0.8 C/m^2. The large values of the piezoelectric coefficients show that polar AlN crystal exhibits a strong microwave piezoelectric effect. Furthermore, the components of the elastic moduli tensor are calculated. The extraordinary electronic, optical, piezoelectric and elastic properties make AlN thin films potential candidates for several opto-electronic, elastic, dielectric and piezoelectric applications.

Optical properties of CdO films prepared by DC planar magnetron sputtering

Optical properties of CdO films prepared by DC planar magnetron sputtering

Role of Pre-Layer Mo Films in Microstructural and Morphological Properties of Over-Layer CIGS Films

ABSTRACTThis study focuses on establishing a microstructural and morphological correlation between CIGS films and its precursor layer of Molybdenum (Mo) coated soda-lime glass (SLG). Therefore, variations in the morphology and microstructural properties of Mo thin films, using DC planar magnetron sputtering, were induced systematically by varying the sputtering pressure from 0.6 to 16 mT with a sputtering power density of 1.2 W/cm2. Subsequently, under fixed deposition conditions (deposition rate and substrate temperature), a growth of Cu(In,Ga)Se2 (CIGS) films was carried out on the Mo-coated SLG substrates, using the 3-stage growth process of the physical vapor deposition (PVD) technique.High-Resolution Scanning Electron Microscopy (HRSEM) was used to examine the Mo and CIGS films morphology. X-Ray Diffraction (XRD) was applied to study in detail the microstructure of Mo and CIGS films. Where, the films’ crystal structure including the preferred orientation and the lattice parameters were determined by the θ/2θ XRD technique and by applying Cohen’s least-square method. Furthermore, Atomic Force Microscopy (AFM) was used to determine the root-mean-square (RMS) surface roughness of the CIGS films.

Factors determining the efficiency of magnetron sputtering. Optimization criteria

We report on the results of experimental study of the dependence of sputtering energy efficiency Kw in a dc planar magnetron sputtering setup on the discharge power, working gas pressure, magnetic field, cathode erosion depth, and the structure of the gas puffing system and anode. We propose that this parameter be used for comparing the degree of perfection of the magnetron design irrespective of the magnetron size and structural features. The results of measurements of Kw in sputtering of Al, Ti, Cr, Cu, Zn, Zr, Nb, Mo, Ag, In, Sn, Ta, W, Pt, and Au are considered. The optimization criterion is worked out for the magnetic system of the magnetron, which ensures the minimal working pressure and the maximal sputtering rate for the cathode. The results are analyzed theoretically.

Optical properties of CdO films prepared by DC planar magnetron sputtering

CdO films have been produced on glass substrates by DC planar magnetron sputtering technique in Ar and O2 gases 1:4 and distance 6cm between cathode and anode and thickness 174 nm. It is observed from optical properties that the films possess transmittance 80% in visible and near infrared region of spectrum and direct band gap values in the rang 2.31-2.4 e V.

Time-resolved tuned diode laser absorption spectroscopy of pulsed plasma

A novel method for time-resolved tuned diode laser absorption spectroscopy has been developed. In this paper, we describe in detail developed electronic module that controls time-resolution of laser absorption spectroscopy system. The TTL signal triggering plasma pulse is used for generation of two signals: the first one triggers the fine tuning of laser wavelength and second one controls time-defined signal sampling from absorption detector. The described method and electronic system enable us to investigate temporal evolution of sputtered particles in technological low-temperature plasma systems. The pulsed DC planar magnetron sputtering system has been used to verify this method. The 2" in diameter titanium target was sputtered in pure argon atmosphere. The working pressure was held at 2 Pa. All the experiments were carried out for pulse ON time fixed at 100 (is. When changing OFF time the discharge has operated between High Power Impulse Magnetron Sputtering regime and pulsed DC magnetron regime. The effect of duty cycle variation results in decrease of titanium atom density during ON time while length of OFF time elongates. We believe that observed effect is connected with higher degree of ionization of sputtered particles. As previously reported by Bohlmark et al., the measured optical emission spectra in HiPIMS systems were dominated by emission from titanium ions [1].

Optical properties of CdO films prepared by DC planar magnetron sputtering

CdOfilms have been produced on glass substrates by DC planar magnetron sputtering technique in Ar and O2 gases 1:4 and distance 6cm between cathode and anode and thickness 174 nm. It is observed from optical properties that the films possess transmittance 80% in visible and near infrared region of spectrum and direct band gap values in the rang 2.31-2.4 e V

The influence of target erosion on the mass spectra of clusters formed in the planar DC magnetron sputtering source

The present paper reports on target erosion as one of the crucial parameters influencing the cluster size distribution. Size distributions of nanosized Cu clusters produced by a DC magnetron sputtering source during the lifetime of several different targets were monitored using a quadrupole mass filter. It is indicated that, during the target lifetime, cluster size distribution continuously shifts towards larger cluster sizes and becomes broader. After a certain operation time the cluster size distribution changes abruptly and the cluster formation is stopped. This happens much earlier than the point at which the erosion groove depth reaches the target thickness. It is suggested that a change in the mass spectra during the target lifetime is caused by the variation of the free metal atom density in the aggregation region. This may be due to the alteration of the sputtering yield. It is shown that the variation of the mass spectra correlates with the angular dependence of the sputtering yield.

Effect of Thickness on Properties of Copper Thin Films Growth on Glass by DC Planar Magnetron Sputtering

Copper thin films with nano-scale structure have numerous applications in modern technology. In this work, Cu thin films with different thicknesses from 50–220 nm have been deposited on glass substrate by DC magnetron sputtering technique at room temperature in pure Ar gas. The sputtering time was considered in 4, 8, 12 and 16 min, respectively. The thickness effect on the structural, morphological and electrical properties were studied by X-ray diffraction (XRD), atomic force microscope (AFM) and four point probe (FPP) measurements, respectively. The results show that by increasing thickness, the copper films crystallinity in (111) direction increases. Also by varying the films thickness the significant changes were observed in the films surface morphology due to the mechanism of films growth. Finally, the relationship between film resistivity and Cu film thickness are investigated in this paper.

The effect of temperature on the structure of tantalum nitride (TaN) thin films deposited by DC plasma

In this work, we report the effect of growth temperature (room temperature, 150, 200 and 250°C) during the deposition of tantalum nitride thin films by a reactive planar DC magnetron sputtering system on the steel substrates, in a constant nitrogen partial pressure of 15% has been studied. The X-ray spectrum of deposited tantalum nitride films indicated an increasing in intensity of sharp peak of hexagonal TaN and was evidence of grain growth at higher temperatures. By increasing temperature the streaks’ directions, observed from AFM micrographs, were varied.

The Effect of Substrate Temperature on the Structure and Morphology of Titanium Nitride Compounds Grown by DC Magnetron Sputtering

The TiN thin films were deposited on p-type silicon (100) substrates using reactive planar DC magnetron sputtering system. The target was 99.99% pure Ti. The reactive sputter gas was a mixture of Ar (99.999%) and N2 (99.999%) with the ratio Ar (97%) and N2 (3%) by volume. Structural characterization of the coating was done using X-ray diffraction (XRD). The surface roughness of the coating was determined using an Atomic Force Microscope (AFM). The reflectivity of thin films was investigated by a spectrophotometer system. The X-ray diffraction measurements showed that by increasing the substrate temperature during the growth, change in crystalline structure will occur. The crystallite size of the films determined by Scherrer’s equation, and the crystallite size measured by AFM also increased by increasing the substrate growth temperature. The surface reflectivity measurements indicate that by increasing the substrate growth temperature, the optical properties of the films changes. The change in optical properties and crystalline structure of the films indicate that substrate growth temperature plays an important role in structure and morphology of the grown layers.

Plasma parameters in a planar dc magnetron sputtering discharge of argon and krypton

The electron energy distribution function (EEDF) and plasma parameters in a planar dc magnetron sputtering discharge in argon and krypton were determined using a Langmuir probe. Two groups of electrons are observed in the discharge. The electron temperature of the cold electrons is roughly independent of the discharge pressure, while the electron temperature of the hot electrons decreases with increased discharge pressure. The electron density increases with increased pressure and is roughly a factor of 2–3 higher for a krypton discharge than for an argon discharge.

Studies on phase dependent mechanical properties of dc magnetron sputtered TaN thin films: evaluation of super hardness in orthorhombic Ta4N phase

The mechanical hardness of the different phases of tantalum nitride (TaNx, x ≤ 1) thin films grown by the reactive planar dc magnetron sputtering technique at 300 °C have been evaluated. The different phases have been prepared by varying the nitrogen (N2) to argon (Ar) gas ratio R in the range 0.04–0.30. The phases present in each sample and their volume fractions are obtained from x-ray diffraction and Ta 4f7/2 binding energy x-ray photoelectron spectra, respectively. The grown TaN thin films are found to contain mainly cubic-TaN0.1, orthorhombic-Ta4N, orthorhombic-Ta6N2.5, hexagonal-TaN0.8 and cubic-TaN phases. The hardness corresponding to each phase has been derived from the experimental hardness values using ‘rule of mixtures’. A super hardness of ∼61.9 GPa is observed in orthorhombic Ta4N phase. With increase in R, a decrease in the surface oxidation of TaN has been observed. The reduced surface oxidation is attributed to the formation of stoichiometric TaN thin films. The surface morphology is found to change considerably with increase in R.

Correlation of ZnO thin film surface properties with conductivity

Technological demands for the fabrication of nanostructured active coatings provide renewed motivation for understanding the properties that control the morphology of the thin film surface. With decreasing structure size, the issues of finite size and shape effects become non-negligible including issues of stability against decay and structural rearrangement. The surface of the wide band gap semiconductor ZnO is known to be very active, with a wide variety of absorption and chemisorptions phenomena taking place. These processes can alter the charge carrier distribution in the sub-surface region and locally change the doping levels. There is a limited amount of literature dedicated to systematic and detailed studies on the surface evolution with growth parameters and their effect on the ZnO surface conductivity under reduction/oxidation. Therefore, this work focuses on the analysis of the thin ZnO film surface properties by studying specific surface parameters such as amplitude related parameters (average roughness, the root mean square), mixed parameters (surface area ratio), functional parameters for characterizing bearing and fluid retention (skewness), and spatial parameters (the fractal dimensions) as they correlate with the film conductivity changes under subsequent exposure to UV light (as reductor factor) and ozone (as surface oxidant agent). All ZnO thin films of different thicknesses were grown by the dc planar magnetron sputtering technique under the same sputtering conditions.

Influence of the external solenoid coil arrangement and excitation mode on plasma characteristics and target utilization in a dc-planar magnetron sputtering system

The influence of external solenoid coil arrangement and excitation mode on plasma characteristics and target utilization was investigated, with an axially external magnetic field Bext being superimposed to the original field of the magnetron source in a dc-planar magnetron sputtering system. The magnetic field configuration was simulated using the finite-element method. Langmuir probe measurement showed that the coil position had a strong effect on the near-substrate plasma parameters, resulting from the variations of magnetic field configuration in the substrate region. Furthermore, it was a relatively simple and effective method to improve the target utilization by supplying a low-frequency ac power to the external coil situated around the magnetron. The target utilization efficiency was highly sensitive to the coil position. The coil was more suitable to be placed in the vicinity of the magnetron for improving the target utilization or near the substrate for increasing the near-substrate plasma density. Finally, a novel method was proposed to simultaneously realize both objects by choosing an appropriate solenoid coil arrangement and excitation mode.

Effects of experimental parameters on the physical properties of non-stoichiometric sputtered vanadium nitrides films

Polycrystalline vanadium nitrides thin films were deposited onto (1 0 0)-oriented silicon wafers by reactive dc planar magnetron sputtering. The influence of the nitrogen gas flow (from 0 to 15 sccm) was studied. Several substrate temperatures were investigated: 150, 400 and 650 °C. Analytical techniques including X-ray diffraction and reflectivity, atomic force microscopy and optical photospectrometry were used to characterize the structure, the morphology and the optical properties of the films. The measured thickness indicates that the deposition rate is decreased (from 3.5 Å for 0 sccm to 1.5 Å for 15 sccm) with increasing nitrogen gas flow. Obtained structures depend on the substrate temperature. The structure of pure vanadium (0 sccm) varies from amorphous phase at 150 and 400 °C to α-V phase at 650 °C. The films crystallize dominantly in β-V 2N 1− x phase at low nitrogen gas flows and in δ-VN 1− x phase at high nitrogen gas flows. The as-deposited VN films were highly textured. The texture seems to depend on the nitrogen gas flow. The root mean square (rms) derived from atomic force microscopy (AFM) varies with the nitrogen gas flow. The optical reflectivity of VN films shows high values in the infrared region.

Characteristics of DLC films by DC magnetron sputtering incorporated with cesium

Diamond-like carbon films were deposited by planar DC magnetron sputtering with cesium vapor. The electrical properties of the plasma were investigated by the I– V measurement of the discharge. The increase in the plasma density and the generation of the negative carbon ions were observed from the I– V curves and deposition rate with different substrate biases. The deposited DLC films were examined by Raman spectroscopy and plasmon energy loss analysis in order to assess their structures. The DLC film obtained with Cs vapor contained a higher sp 3 fraction than that without Cs vapor. This result implied that the negative carbon ions produced by Cs vapor participated in the deposition through the subplantation process. From experimental results, it is expected that Cs vapor addition to conventional magnetron sputtering system makes possible the deposition of higher quality DLC as well as large area deposition.

Titanium nitride coatings on copper alloy prepared by dc reactive magnetron sputtering

The theory of deposition of TiN by dc magnetron sputtering for wear protection of the surfaces is well known using different ferrous substrates. This theory apparently, is not so true for other non-ferrous materials. The present work shows the study of some characteristics of TiN deposition on a ternary copper alloy (Cu–3% Ti–1% Cr) with the purpose of modifying their superficial properties, and in this way allowing to enlarge the alternatives of use of this alloy. The wear, microhardness and adhesion of the films deposited have been studied under different conditions of applied current, Ar/N 2 flow ratio and bias voltage by means of dc planar magnetron sputtering. By this study we concluded that, unlike the case of steel, for increasing the wear resistance of the alloy it is advisable not to use bias voltage during TiN deposition. It is desirable to obtain an open columnar structure in order to increase the wear resistance and the critical load in scratch testing.

A study on formation of Al and Al2O3 on the porous paper by DC magnetron sputtering

Understanding the mode of transport of water vapor through the film is important for improving the moisture barrier properties of metallized porous papers. For the synthesis of Al metallized porous papers, it was carried out by DC planar magnetron sputtering with various target power densities and film thickness. To correlate film characteristics with moisture barrier properties, film properties were determined by X-ray diffraction, scanning electron microscopy, Auger electron spectroscopy and evaluations of water vapor permeability (WVP). It changed preferred orientations from Al(111) to α-Al2O3(110) reacted with thermal activated oxygen from the paper as film thickness increase and the minimum WVP mean is 2.16×10−7 gmm/m2hkPa at 6.3 W/cm2, 2 μm and the maximum is 2.00×10−8 gmm/m2hkPa at 1.2 W/cm2, 0.2 μm.

Effect of pressure on dc planar magnetron sputtering of platinum

Argon pressure in the 10 to 200 mTorr range was shown to have a profound effect on the deposition characteristics of nonreactive platinum. Two features were observed. The film thickness does not vary rapidly with deposition pressure, and, the density of the film varies rapidly from near bulk to a much lower value at pressures above 50 mTorr. Films at low pressures have a density of ∼20.8 g/cm3 and well defined “columnar structure.” At high pressures (200 mTorr), the density drops to as low as ∼9 g/cm3. Porosity, or void structure, is dominant at high pressure and the columnar structure is still present.