Effect Of Substrate Bias Voltage Research Articles

Effects of substrate bias voltage on conductivity and internal stress of TiN films

In order to make the service life of microelectronic devices longer, titanium nitride electrode films need to meet the requirements of high electrical conductivity and low internal stress. In this paper, the effect of substrate bias voltage on the properties of titanium nitride films prepared by direct current (DC) reactive magnetron sputtering was studied systematically. The changes of titanium nitride films properties were investigated in detail from the aspects of resistivity, growth rate, crystal orientation, roughness and internal stress. The results show that the introduction of substrate bias voltage is conducive to the formation of dense titanium nitride films. Considering that the resistivity and internal stress of titanium nitride film vary with substrate bias voltage, the film deposited at substrate bias voltage of -100 V is selected as the electrode film material with the best performance (resistivity of 47.5 μΩ·cm, roughness of 1.1 nm and internal stress of -5.6 GPa).

Effect of bias voltages and interlayer design on microstructure, mechanical properties, and adhesion performance of AlCrSiN coatings deposited using HiPIMS

This study fabricated AlCrSiN coatings from six alloy targets (Four Al7Cr3 targets and two Cr9Si1 targets) using high-power impulse magnetron sputtering (HiPIMS) with a focus on the effects of substrate bias voltage (−30 to −90 V) on deposition rate, microstructure, crystal orientation, residual stress, and mechanical properties. Electron Probe Microanalysis (EPMA) and X-ray Diffraction (XRD) results revealed that variations in bias voltage had little impact on the element composition or crystal structure (FCC) of AlCrSiN coatings; however, under high bias voltage (exceeding −60 V), the preferred orientation shifted from the (111) plane to the (220). Increasing the bias voltage from −30 to −90 V was shown to reduce the deposition rate (from 42.2 to 37.6 nm/min) and the thickness of the AlCrSiN coating (from 2.9 to 2.6 μm). It was also shown to increase the hardness (from 2147 to 3658 HV) and residual stress (from −0.01 to −0.59 GPa) by reducing the grain size and allowing the formation of a denser structure. Various interlayer designs (AlCr/AlCrxNy/AlCrN, CrSi/AlCrxNy/AlCrN, AlCr/CrSixNy/CrSiN, CrSi/CrSixNy/CrSiN) were assessed in terms of adhesion strength between the AlCrSiN and substrate. Under the same AlCrSiN deposition condition, with the bias voltage set to −60 V, the highest adhesion strength (from 32.28 to 45.81 N) was achieved using a CrSi/CrSixNy/CrSiN interlayer structure.

Effects of Substrate Bias Voltage on Structural and Optical Properties of Co-Sputtered (AlxGa1–x)2O3 Films

Effects of Substrate Bias Voltage on Structural and Optical Properties of Co-Sputtered (AlxGa1–x)2O3 Films

The effect of substrate bias voltage on the mechanical and electrochemical corrosion properties of multilayered CrN/CrAlN coatings produced by cathodic arc evaporation

AbstractThe multilayered CrN/CrAlN film was deposited on the SS420 substrate by cathodic arc evaporation technique. The effect of substrate bias voltage was investigated on the microstructure, surface morphology, and mechanical and electrochemical corrosion properties of the deposited film. The deposited CrN/CrAlN coatings were characterized by X‐ray diffraction and field emission scanning electron microscope techniques. Mechanical properties, corrosion resistance, and surface morphology of the coated samples were studied by nano‐indentation, polarization test, electrochemical impedance spectroscopy, and atomic force microscopy, respectively. Adhesive and dense nanostructure CrN and CrAlN phases were successfully deposited on the substrate. The refinement of the coating crystallite was observed from 31.2 to 24.3 nm by increasing the substrate bias voltage, this improved the mechanical properties of the coating. The number of macroparticles, pinholes and porosities, and the surface roughness of coatings significantly decreased by increasing the substrate bias voltage. The CrN/CrAlN coating reduced the corrosion current density in contrast to the SS420 substrate. Better corrosion resistance was obtained for the coating deposited at 150 V of bias voltage due to lower defects in the film structure.

Effect of Substrate Bias Voltage on Microstructure and Mechanical Properties of Cr-Nb-Ti-Zr-N-O Ceramic Thin Films Produced by Reactive Sputtering

Hard coatings are applied in various applications to protect substrates from wear and corrosion. In the present study, multi-element ceramic films are deposited by reactive sputtering. The level of substrate bias voltage (−50, −125 and −200 V) is changed to investigate the structural and mechanical properties of Cr-Nb-Ti-Zr-N thin films. Chemical analysis (using EDS, XRD and Raman spectroscopy) reveals that these thin films (with a high amount of oxygen) are composed of a nanocomposite phase structure (amorphous and nano-crystalline phases). CrO2 and NbxN crystalline phases exist in an amorphous matrix in the coatings. By increasing the substrate voltage (from −50 to −200 V), the nitrogen content (from 30 to 40 at. %) increases, and CrxN crystalline phases are generated in S125 and S200. Morphological, topological and image analysis (employing FESEM and AFM) data show that the intermediate level of substrate bias voltage (sample S125) can produce a uniform surface with minimum defect density (15%). In addition, S125 has the minimum level of roughness (16.6 nm), skewness (0.2) and kurtosis (2.8). Therefore, the hardness, toughness and wear resistance (extracted from indentation and scratch tests) of this sample is maximum (H is 24.5 GPa and H/E is 0.107), while sample S50 shows complete fracture and delamination.

Effect of substrate bias voltage on structural and tribological properties of W-Ti-C-N thin films produced by combinational HiPIMS and DCMS co-sputtering

Protective multi-component thin films at the surface of cutting tools have been significantly developed to reduce wear and friction. The present work investigates the effect of substrate bias voltage on the structural-tribological relations of W-Ti-C-N thin films produced by HiPIMS and DCMS co-sputtering. Chemical analysis of the coatings is obtained and composite phase structure is revealed. Morphology of the coatings illustrates that defectless surfaces may be achieved. Topographical parameters are investigated by employing graphical software. Indentation, scratch and pin-on-disk tests (pin is AISI 52100 steel) are applied to study mechanical behaviors of the films. To produce a wear-resistant film, a median bias voltage (−60 V) and as a result, optimum content of tungsten concentration (19.2 at. %), grain size (42.8 nm) and average peak interval (188 nm) is required. Finally, a model based on the representative volume element is developed to show crack propagation and delamination.

Effect of Substrate Bias Voltage on Infrared Characteristics of TiN Films

Effect of Substrate Bias Voltage on Infrared Characteristics of TiN Films

Effect of bias voltage on the structure and properties of CuNiTiNbCr dual-phase high entropy alloy films

The dual-phase structure has been proved to overcome the effect of strength-ductility trade-off of high-entropy alloys. However, most of the high entropy alloy films with larger atomic size difference tend to form a single amorphous structure under non-equilibrium deposition conditions such as magnetron sputtering. In this study, the dual-phase CuNiTiNbCr high entropy alloy film containing the Cu-rich FCC alloy phase and amorphous phase were synthesized by high-power pulsed magnetron sputtering at different bias voltages. The poor affinity of copper with other elements led to the segregation and enrichment of copper to form a Cu-rich FCC phase. The effects of substrate bias voltage on the microstructure, mechanical and corrosion properties of the films were investigated. With the increase of bias voltage, the content of copper in the film decreased, the stress state of the film changed significantly, and the compactness of the structure was improved. The hardness of all films was higher than that of most other high entropy alloy film systems. The films deposited under low bias voltage have better toughness. The film deposited at －50 V showed the best wear resistance due to a combination of high hardness and good toughness. The film deposited at －150 V showed the best corrosion resistance since it had the lowest self-corrosion current density (6.1 ×10−8 A/cm2), which was due to its compact structure and lower impurity content.

Effects of substrate bias voltage on the phase structure, mechanical and wear resistance properties of tungsten boride films

Tungsten boride (WBx) films are widely used in material protection due to their high hardness. However, the wear resistance of these films needs to be improved through enhancing their toughness while maintaining their high hardness in order to significantly extend the service life of mechanical parts. Based on the characteristics of structural diversity caused by differences in the boron (B) content in WBx, in this study, magnetron sputtering was used to deposit WBx films at different substrate bias voltages, with the aim of regulating the microstructure and further optimizing the mechanical and wear resistance properties of the films. Increasing the bias voltage helps to reduce the B content of WBx without changing the original dual-phase (WB2 and W2B) structure. The synergetic effects of the dual-phase structure, solid solution strengthening of B atoms, and gradual increase in the compressive stress are conducive to enhancing the hardness of WBx. Meanwhile, the decrease in B content leads to an increase in the relative content of the W2B toughening phase, improving the film toughness. For the film grown at −120 V, the dual optimization of hardness and toughness is achieved, resulting in super wear resistance in the atmosphere at an ultra-low wear rate of 5.2 × 10−18 m³/Nm. However, although the reduction of B content improves the metallicity and toughness, due to the disappearance of the WB2 hard phase, the hardness and wear resistance of the WBx film are weakened at bias voltages above −120 V.

Effect of Substrate Bias Voltage on Structure and Corrosion Resistance of AlCrN Coatings Prepared by Multi-Arc Ion Plating

Effect of Substrate Bias Voltage on Structure and Corrosion Resistance of AlCrN Coatings Prepared by Multi-Arc Ion Plating

Effects of Substrate Bias Voltage on Structure of Diamond-Like Carbon Films on AISI 316L Stainless Steel: A Molecular Dynamics Simulation Study.

With the recent significant advances in micro- and nanoscale fabrication techniques, deposition of diamond-like carbon films on stainless steel substrates has been experimentally achieved. However, the underlying mechanism for the formation of film microstructures has remained elusive. In this study, the growth processes of diamond-like carbon films on AISI 316L substrate are studied via the molecular dynamics method. Effects of substrate bias voltage on the structure properties and sp3 hybridization ratio are investigated. A diamond-like carbon film with a compact structure and smooth surface is obtained at 120 V bias voltage. Looser structures with high surface roughness are observed in films deposited under bias voltages of 0 V or 300 V. In addition, sp3 fraction increases with increasing substrate bias voltage from 0 V to 120 V, while an opposite trend is obtained when the bias voltage is further increased from 120 V to 300 V. The highest magnitude of sp3 fraction was about 48.5% at 120 V bias voltage. The dependence of sp3 fraction in carbon films on the substrate bias voltage achieves a high consistency within the experiment results. The mechanism for the dependence of diamond-like carbon structures on the substrate bias voltage is discussed as well.

Tuning structural, electrical and mechanical properties of diamond-like carbon films by substrate bias voltage

Diamond-like carbon (DLC) thin films are deposited by unbalanced RF magnetron sputtering at substrate bias voltages to tune the ratio of the sp3 to sp2 bonds and hydrogen composition in optimized Ar: CH4 ambient. The effect of substrate bias voltage on the sp2 and sp3 bonding ratios and hydrogen concentration is correlated to the physical and elastic properties for the optimized DLC film. Raman spectroscopy qualitatively established sp3/sp2 bonding ratios from the ID/IG ratio at various substrate bias voltages and the trend is in agreement with XPS data. High H content of at least 18.00 ± 2.00 at. % is evaluated from photoluminescence background for all substrate bias voltages. Applying an empirical approach to the ID/IG ratios, we derive the Tauc band gaps in the range between 1.51 and 1.57 eV. The highest band gap correlates to the highest resistivity values (131 × 102 Ω.cm) measured for DLC films deposited at the highest bias voltage of −100 V and with lowest H content. As DLC thin films deposited at −100 V exhibit optimal properties, the elastic constants are subsequently evaluated using the Surface Elastodynamic Greens functions to the discrete phonon dispersion obtained by surface Brillouin scattering. Enhancement in bulk, shear and elastic moduli is ascribed to higher sp3/sp2 ratio and predominantly to H content.

Effect of substrate bias voltage on the mechanical properties of AlTiN/CrTiSiN multilayer hard coatings

During physical vapor deposition (PVD), bias voltage is usually applied to the substrate for tuning the ion energies and tailoring the coating structure and mechanical properties of a protective hard coating for specific applications. In the present study, AlTiN/CrTiSiN multilayer coatings were deposited by a multisource cathodic arc ion deposition system with negative substrate bias voltages ranging from −20 to −180 V. During the coating process, graded CrN, CrN/AlTiN and CrTiSiN were deposited as interlayers to enhance adhesion strength of the coatings. Multisources of Cr, TiSi and AlTi alloy targets were used. Residual stresses and mechanical properties of AlTiN/CrTiSiN multilayer coatings deposited under various bias voltages were investigated. All the AlTiN/CrTiSiN multilayer coatings possessed higher hardness values (38.2–39.6 GPa) than AlTiN (32.5 GPa). As compared to the monolithic AlTiN, which had high residual stress of −9.8 GPa, the AlTiN/CrTiSiN multilayer coatings showed lower residual stresses of −2.4~ −9.1 GPa. The higher bias voltage was used the higher residual stress was observed. The AlTiN/CrTiSiN multilayer coating deposited at −20 V possessed the lowest residual stress (- 2.4 GPa). A cyclic impact test with high frequency were performed to evaluate the impact fatigue performance. The AlTiN/CrTiSiN multilayer coating deposited at −20 V showed the highest H/E (0.082) and H3/E2 (0.265) values to resist impact fatigue. The design of AlTiN/CrTiSiN multilayer coatings via low bias voltage can decrease residual stress and possessed good impact fatigue performance. Although the AlTiN/CrTiSiN coating deposited at high bias voltage of −180 V had similar hardness value to other AlTiN/CrTiSiN coatings under −20 V and −100 V, worse resistance to impact fatigue were found.

Effects of substrate bias voltage on structure and internal stress of amorphous carbon films on γ-Fe substrate: Molecular dynamics simulation

In this paper, the deposition process of amorphous carbon (a-C) films on γ-Fe substrate was simulated by molecular dynamics (MD). The effects of substrate bias voltage (abbreviated as bias) on structure and internal stress of a-C films was investigated. The results showed that the growth process of a-C films on γ-Fe substrate can be divided into five stages, namely, the diffusion stage of C atoms, island-like nucleation stage of a-C films, formation stage of the pseudo diffusion zone, diffusion stage of Fe atoms and stable growth stage of a-C films. The structure of a-C films after deposition can be divided into four zones, namely, the substrate zone, pseudo diffusion zone, intrinsic zone and surface zone. The intrinsic zone is the main part of a-C films, and its structure is mainly composed of sp3-C and sp2-C atoms. The percentage of sp3-C atoms is fluctuated with the increase of bias. When bias is 25 V, the percentage of sp3-C atoms is the largest, which is 26.19%. When bias is 75 V, the percentage of sp3-C atoms is the smallest, which is 23.92%. The percentage of sp2-C atoms is increased with the increase of bias. When bias is 75 V, the percentage of sp2-C atoms is the largest, which is 73.69%. With the increase of bias, the internal stress of the intrinsic zone is firstly increased. When bias is 25 V, the internal stress is the highest, which is 6.94GPa and then is decreased gradually. The pseudo diffusion zone is a transition zone between a-C films and γ-Fe substrate, and is a mixed zone composed of C and Fe atoms. With the increase of bias, the internal stress in the pseudo diffusion zone is decreased gradually. When bias is 75 V, the internal stress is the lowest, which is 0.40GPa.

Effect of substrate bias voltage on the mechanical properties and deformation mechanisms in the nanostructured Ti-22Nb-10Zr coating

The manufacturing of future implants based on NiTi shape memory alloys, like stents, orthodontic archwires, intracranial aneurysms..., clips aims to eliminate the cytotoxicity and allergic problems associated with the release of nickel ions. In this context, the design of β-rich Ti-22Nb-10Zr (mass.%) coating by magnetron sputtering, with a non-linear elastic behavior and tunable mechanical properties, offers a novel approach for the development of a new biocompatible implants with self-adjusting mechanical properties. The XRD and TEM analyses reveal that microstructure consisting of hexagonal close-packed (α-phase), prevalent body-centered cubic (β-phase) and orthorhombic (α″-phase) nanograins, which can be tuned during the deposition by a single parameter – applied bias voltage as a result of the activation of a stress-induced martensitic transformation (β → α″). We found that the minimum stress value to trigger the SIM transformation must be higher than 712 MPa (bias −63 V). The application of higher bias voltage values alters the main deformation mechanism, from a combination of reversible SIM transformation and mechanical twinning to dislocation slip, causing the compressive residual stresses to decrease from 712 to 120 MPa, the hardness increases from 2,1 to 4,1 GPa, and the coating stops showing low Young's modulus (<50 GPa) and non-linear elastic behavior.

Effect of substrate bias voltage on the composition, microstructure and mechanical properties of W-B-C coatings

Commercial ceramic protective coatings usually exhibit high hardness, but low ductility impairs their performance and application-oriented properties. Accordingly, a state-of-the-art magnetron sputtered W-B-C coating can be a promising coating for the tooling industry due to its hard yet tough characteristics. In the present study, we have employed substrate biasing to enhance the delivered energy to the growing film and have investigated the effect of bias voltage on the structural and mechanical behavior of W-B-C coatings. The investigations revealed that increasing the substrate bias voltage enhanced the re-sputtering of B and C atoms and subsequently varied the chemical composition of the coatings and significantly decreased the growth rate. It also enhanced the crystallinity of the coatings. We demonstrate how the bias voltage led to an unusual transition from a featureless to a columnar microstructure. Furthermore, it was observed that as the substrate bias voltage increased from 0 V to −125 V, the compositional and structural changes resulted in a slight decrease of the hardness, while a further increase in the bias voltage to −200 V enhanced the hardness. This increase was attributed to the suppression of dislocation movement and grain boundary deformation processes by solute segregation and by lattice defects.

Quantification of the Effects of Coating Parameters on the Properties of TiAlZrN Coatings

In this study, TiAlZrN layer was coated on AISI H13 substrate surface with variable substrate bias voltage, Zr target current, and ambient pressure deposition parameters by using closed field unbalanced magnetron sputtering (CFUBMS) technique. The main goal of this paper is to determine the effect percentages of these variable parameters on the properties of TiAlZrN coatings by Analysis of Variance (ANOVA). These coating properties include average grain size, thickness, hardness, adhesion strength and wear resistance. The numerical data obtained as a result of this study will shed light on the select of parameters which have a direct effect on coatings to the researchers who will work on this topic. The parameters used as variables in the deposition process were leveled with Taguchi experimental (33) design method. Average grain size and thickness of coatings were established by SEM images. The average grain sizes of coatings were between 290 and 440 nm and the most effective parameter was substrate bias voltage with 58.4 %. The hardness, adhesion strength and wear properties of the coatings were determined using micro hardness tester, scratch test and ball on disc wear device respectively. The maximum hardness of coatings was 1674 HV, while the wear resistance was increased by 37 times compared to the substrate material. The maximum adhesion strength value of the coatings was reached 56N. The superiority of the effect of substrate bias voltage on the hardness, adhesion strength and wear resistance of the coatings compared to other deposition parameters was again prominent (respectively 86.15%, 53.63% and 70.86%). Also, the hardness and wear resistance properties were found to be directly related to each other. The sample with the highest coating hardness also showed the highest wear resistance performance. In the sample with the lowest hardness, this situation found to be similar.

Effect of Substrate Bias Voltage on the Structure and Properties of Mos2-Ti Composite Films on Titanium Alloy Surface

In order to discuss the effect of negative bias on the structure and properties of MoS2-Ti composite films on titanium alloy surface. In this paper, MoS2-Ti solid lubrication films were deposited on titanium alloy surface by unbalanced magnetron sputter. The effects of negative bias on the structure and properties of MoS2-Ti solid lubrication films were discussed. The morphology, phase, hardness, friction and wear resistance and wear mark morphology of solid lubricating film were analyzed and tested by scanning electron microscope, XRD, microhardness tester, friction and wear tester and surface profilometer. The results shows that wwhen the negative bias voltage was -150V and -200V, the structure of MoS2-Ti films is compact and the bonding with the substrate is compact. With the increase of negative bias voltage, the hardness of the film increases gradually. The wear rate of the films prepared at -150V bias voltage is the lowest, which is 2.2×10−17mm3/(N×m). The MoS2-Ti composite films deposited on the surface of titanium alloy exhibit excellent tribological properties with low friction and wear resistance, which effectively improves the surface friction and wear properties of titanium alloy.

Static and Quasi-Static Drain Current Modeling of Tri-Gate Junctionless Transistor With Substrate Bias-Induced Effects

In this paper, a surface potential-based drain current model is developed to explore the static and quasi-static performance of substrate-biased tri-gate junctionless field-effect-transistors (TGJLFETs). The effects of substrate bias voltage on surface potential, charge density, and drain current are analyzed. The 2-D Poisson’s equation is solved to obtain front and back surface potentials incorporating the effect of substrate bias voltage for a long-channel TGJLFET. The front and back surface potentials are subsequently utilized to obtain total conduction charge density and drain current. Further, short-channel and quantum mechanical corrections are incorporated in the model to use it for scaled devices. Moreover, the terminal charges calculated using Ward–Dutton’s charge partitioning scheme are utilized to model the transcapacitances and quasi-static drain current for TGJLFET. Further, an equivalent large-signal transient model of the device is implemented in SPICE using Verilog-A, and the transient behavior of inverter and ring oscillator circuits are simulated and studied. The models are validated using a 3-D Visual TCAD device simulator from Cogenda Pvt. Ltd.

Effect of bias on structure mechanical properties and corrosion resistance of TiNx films prepared by ion source assisted magnetron sputtering

Titanium nitride (TiNx) films were deposited on 304 stainless steel and silicon (100) wafers by ion source assisted magnetron sputtering. The effect of substrate bias voltage on the preparation and properties of TiNx films was investigated. The results show that as the substrate bias voltage increases from 0 V to −400 V, the deposition rate of TiNx film decreases significantly and the density increases, which can be attributed to the re-sputtering effect at high ion bombardment. The texture of TiNx films varies gradually from (111) to (200) with the increase of energy delivered into the growing film. The hardness of the film deposited under −200 V bias voltage reaches the maximum value, 12.9 GPa. Meanwhile, the toughness and corrosion resistance of the film reach a maximum at a bias voltage of −400 V. In conclusion, the density, hardness, toughness and corrosion resistance of TiNx films can be increased by changing the substrate bias voltage.