Influence Of Sputtering Power Research Articles

Sputtered Sn-doped Ga2O3 films under balance controlled of energy supply and ion bombardment for solar-blind detection application

The characteristics of amorphous Sn-doped Ga2O3 films deposited using radio frequency magnetron sputtering at room temperature under different sputter powers have been demonstrated. A balance mechanism of energy supply and ion bombardment controlled by sputter power has been found during the deposition. The increasing growth rate as power can be due to the increased yield sputtering species indicated by an in situ optical emission spectroscopy. As the power increases to 700 W, an obvious change from discrete nanoparticles to flat-continuous film can be observed because of sufficient energy supply for oxidation reaction, which leads to the maximum ratio of lattice oxygen and Sn4+ indicating the optimal film quality and conductive property. However, a non-negligible high energy ion bombardment presented at 900 W leads to the degraded film quality. The influence of sputtering power on Sn-doped Ga2O3 solar-blind photodetectors is demonstrated. It can obtain a good performance with an ultra-low dark current density of 2.2 × 10−11 A/cm2, a substantial light-dark current ratio of 1.08 × 103 and fast rise/decay time of 1.59 s/0.54 s at 700 W. The revelation of the role of sputtering power on the properties of Sn-doped Ga2O3 films may offer an interesting direction for low-cost and high-performance solar-blind photodetectors.

A facile way to tune the chemical composition of gas-phase synthesized nanoclusters

Cluster beam deposition (CBD) represents a powerful and versatile gas-phase synthesis method to fabricate nanoclusters that are in demand for various fields. However, the ready control of the chemical composition is of great significance and is still a challenge. In this work, the influences of sputtering power and Ar fluxes on the composition, size and shape of Sm-Co nanoclusters fabricated by the CBD method using a single composite target have been systematically investigated. The chemical composition of nanoclusters has been characterized by high-angle annular dark-field (HAADF) images and EDS of high-resolution transmission electron microscopy. As the sputtering power increases or the Ar fluxes decrease, the Co concentration in nanoclusters gradually increases, the variation of composition in nanoclusters is consistent with the electrocatalytic measurement results. The mechanism by which the composition changes is proposed to be associated with the distinct scattering for Sm and Co by Ar atoms. The composition of nanoclusters can be quantitatively tuned over a wide range by Ar fluxes and sputtering power. We demonstrate an effective way to synthesize nanoclusters with various chemical compositions and manipulate their corresponding functional properties, which advances the design and synthesis of nanoclusters and may be important for both basic research and applications.

Influence of sputtering power on optical, electrical properties and structure of aluminum-doped indium saving indium-tin oxide thin films sputtered on preheated substrates

The indium tin oxide (ITO) thin film doped with aluminum oxide with reduced to 50 mass% indium oxide content were fabricated by co-sputtering of the ITO and Al2O3 targets. Thin films were deposited in mixed argon–oxygen atmosphere onto glass substrates preheated at 523 K. The dependence of the electrical, optical and structural properties of the films on radio frequency (RF) power of the Al2O3 target was investigated. The obtained thin films were characterized by means of four-point probe, Ultraviolet-Visible-Infrared (UV–Vis-IR) spectroscopy, x-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS). Doping of the ITO thin films by Al2O3 resulted in increasing transmittance of films. It has been found that the film sputtered under optimum condition showed values of volume resistivity 713 µΩcm, electron mobility 30.8 cm2V−1s−1 and carrier density 2.87 × 1020 cm−3.

Influence of sputtering power on the switching and reliability of ferroelectric Al0.7Sc0.3N films

The sputtering power dependence of 40 nm thick Al0.7Sc0.3N ferroelectric properties was characterized from 200 to 300 W. X-ray rocking curve revealed higher orientated growth into the c-axis with higher sputtering power. Films formed by high power showed reduced leakage current with a higher breakdown field, enabling one to apply the high field for ferroelectric switching. A high remnant polarization (P r) of 130 μC cm−2 was obtained with a coercive field (E c) of 6 MV cm−1. The switching cycle test revealed a wake-up effect for all the films; increasing the leakage current and modifying the E c. We anticipate the change is attributed to the existence and the generation of nitrogen vacancies (V N) in the films.

Effect of sputtering power on piezoresistivity and interfacial strength of SiCN thin films prepared by magnetic sputtering

SiCN ceramics show large potential in high temperature pressure sensors with excellent stability up to 1000 °C, as it is changeling for the most of the existing pressure sensors to work stably at a temperature above 600 °C. However, bulk SiCN ceramics are not compatible to microelectronic processing and exhibit slow response due to viscoelasticity, it is necessary to propose alternative method to prepare SiCN functional structures. In this work, SiCN piezoresistive thin films are prepared by magnetron sputtering, and the influence of sputtering power on their piezoresistive properties and interfacial strengths are studied. The gauge factors of SiCN films range from 2786 to 4714 at various sputtering powers, which are significantly higher than the range from 46 to 1105 for existing piezoresistive thin films. Upon an optimal sputtering power of 75 W for silicon nitride target, the obtained SiCN sample show the largest gauge factors in a large range from 0.5 to 3.4 MPa. Furthermore, the SiCN thin films present high critical loads up to 36.5 N in scratch tests and indicate strong interfacial adhesion with substrate. This work provides an important reference for developing SiCN-based MEMS pressure sensors.

Fabrication and characterization of high performance InAlZnO Schottky barrier diode and its application in ultraviolet photodetection

High-performance InAlZnO (IAZO) Schottky barrier diodes (SBDs) with top Pd/IAZO Schottky contact were fabricated, and the influence of sputtering power used to prepare IAZO films on the device performance was investigated. The 50 W-fabricated IAZO SBD exhibited the relatively best electrical properties, including a close-to-unity ideality factor (1.03), a high rectification ratio (1.83 × 107), a low series resistance (237.5 mΩ cm2), large barrier heights (0.87 and 0.82 eV), and a small barrier inhomogeneity (0.05 eV), which was mainly due to the least background doping density (8.43 × 1015/cm3) and interface state density (4.30 × 1010/eV cm2) at 50 W. Meanwhile, the IAZO SBDs prepared at 50 W also displayed the best device uniformity and highest reverse breakdown voltage (−15.23 ± 0.405 V). A 50 W-fabricated IAZO SBD with a horizontal structure was then applied to the ultraviolet photodetector, and it showed good detection effect, especially the fast response with an average rise time of 0.208 s and an average decay time of 0.094 s. Our study indicates the great research value and development potential of IAZO SBDs in future integrated circuits and other fields.

Study on the resistivity and infrared emissivity of TiNx films at different sputtering power

TiNx films with low infrared emissivity were prepared using DC reactive magnetron sputtering technique. The influence of sputtering power (50, 80, 100, and 200 W) on the morphology, structure, adhesion force, resistivity and infrared emissivity was investigated systematically. The thickness of the prepared TiNx films was in the range of 381–987 nm. The films grew with preferred orientation of (200) plane at lower sputtering power, while the preferred orientation was (220) plane at higher sputtering power. The N/Ti stoichiometry ratio increased from 0.67 to 0.96 with the increase of sputtering power, and the deposited TiNx thin films were off stoichiometry. Due to more formation of bonds of Ti–N in TiNx crystal, the adhesion force increased with increasing of sputtering power. The resistivity and infrared emissivity of TiNx films first deceased, and then increased with the increase of sputtering power. Defects in TiNx films prepared at 50 W led to high resistivity and infrared emissivity. The lattice distortion caused by Ti atoms was considered to play an important role in the increase of the resistivity of TiNx films at 200 W. The decrease of carrier density caused by decreased nitrogen vacancies should be the reason for the increase of the infrared emissivity of TiNx films at 80–200 W.

Structural and mechanical properties of amorphous Si–C-based thin films deposited by pulsed magnetron sputtering under different sputtering powers

Amorphous Si–C-based (a-SiC) thin films as protective coating have been attracting more and more attentions. But there are contradictory reports in the literature about the effect of sputtering power on the structural and mechanical properties of a-SiC films. Here, the influence of sputtering power on structural and mechanical properties of a-SiC thin films deposited by pulsed magnetron sputtering have been investigated. The results show that as-prepared films have a columnar structure and cauliflower-like pattern at lower sputtering power (100 W). Increasing the sputtering power from 100 W to 180 W, the columnar feature disappears and the thin films become denser. Meanwhile, the density of Si–C bond increases and the sp3/sp2 radio decreases. The hardness (H) and elastic modulus (E) of the a-SiC thin films increase when the sputtering power increases from 100 to 120 W and then their almost keep constant when the sputtering power increases from 120 to 140 W. Further increases in sputtering power, the H and E increase again. The maximum H and E are about 20.2 GPa and 223.1 GPa at 180 W, respectively. Reason for excellent mechanical property is proposed in combination with the theory analysis and experiment results.

Enhancement of thermoelectric performance of N-type Bi2Te3 based thin films via in situ annealing during magnetron sputtering

In this work, n-type Bi2Te3 based thin films were prepared in 300 °C via DC magnetron sputtering, and influences of sputtering power and annealing time on thermoelectric properties of films were investigated. The raise of sputtering power brings about the improvement of deposited rate and enhancement of grain size. Taking the consideration that the large-sized grains are to phonon scattering, we determine the medial power of 30 W as the basic technical parameters for the purpose of further optimizing performance through an in situ annealing process. Subsequently, thin-film treated by in situ annealing process acts out an obvious reduction in electrical conductivity attributed to the decrease in carrier concentration. Especially, the film annealed for 40 min shows an enhancement in the Seebeck coefficient and leads to a maximum power factor 0.82 m W m−1 K−2 at 543 K.

Optical properties of amorphous Ta2O5 thin films deposited by RF magnetron sputtering

Optical properties including refractive indices, extinction coefficient, thickness and both optical direct and indirect band gaps of the Ta2O5 thin films deposited by RF magnetron sputtering were determined in this work. The influence of sputtering power, which varies from 70 to 130 W, on microstructure and optical properties of the films were investigated as well. Phase structure, surface morphology, optical transmittance and optical constants of the samples were characterized by X-ray diffraction, atomic force microscopy, spectrophotometry and ellipsometry, respectively. The results show that deposition rate of the films increases with increasing sputtering power, and the maximum deposition rate, 2.1 nm/min, is achieved at 130 W, while the minimum one, 0.84 nm/min, is obtained at 90 W. The as-deposited thin films are amorphous according to the X-ray diffraction. Good surface quality featured by dense and compact microstructure is obtained at lower and higher sputtering powers while some micro-pores are found in the film deposited at medium sputtering powers. The optical constants, such as refractive index, extinction coefficient, and thickness of the Ta2O5 thin films were determined as a function of wavelength based on the ellipsometry measurements and fittings, and the dispersive refractive index was obtained for each sputtering power. The optical constants have been verified by comparing the measured transmittance spectra with the simulated ones, as they are consistent well with each other. Direct bandgap ranging from 4.05 to 4.18 eV and indirect bandgap ranging from 4.53 to 4.66 eV were acquired for the films deposited with the aforementioned sputtering powers.

Influence of Sputtering Power on the Electrical Properties of In-Sn-Zn Oxide Thin Films Deposited by High Power Impulse Magnetron Sputtering

In-Sn-Zn oxide (ITZO) thin films have been studied as a potential material in flat panel displays due to their high carrier concentration and high mobility. In the current work, ITZO thin films were deposited on glass substrates by high-power impulse magnetron sputtering (HiPIMS) at room temperature. The influence of the sputtering power on the microstructures and electrical performance of ITZO thin films was investigated. The results show that ITZO thin films prepared by HiPIMS were dense and smooth. There were slight variations in the composition of ITZO thin films deposited at different sputtering powers. With the sputtering power increasing from 100 W to 400 W, the film’s crystallinity was enhanced. When the sputtering power was 400 W, an In2O3 (104) plane could be detected. Films with optimal electrical properties were produced at a sputtering power of 300 W, a carrier mobility of 31.25 cm2·V−1·s−1, a carrier concentration of 9.11 × 1018 cm−3, and a resistivity of 2.19 × 10−4 Ω·m.

Influence of Sputtering Power of ZrB2 Target on Structure and Properties of Nanocomposite Zr-B-O Films

The nanocomposite Zr-B-O films based on ZrB2 and ZrO2 are successfully deposited on Si (100) and stainless-steel substrates via a multi-target magnetron co-sputtering system. The influence of the sputtering power of ZrB2 target on sample structure and performance was analyzed by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectrometer (XPS). Nano scratch tests were conducted to measure the films’ mechanical properties. Their oxidation resistance in an aerobic environment was tested by high-temperature oxidation in a muffle furnace. Corrosion behaviors of the Zr-B-O films were evaluated by potentiodynamic polarization and electrochemical impedance spectroscopy. It shows that the interior of the composite films has a high degree of non-crystallization. The maximum hardness (26.76 GPa) and corresponding elastic modulus (268.05 Gpa) of the film were obtained at the sputtering power of 120 W. The hardest film also shows the better oxidation resistance with a mass change of around 0.1% before and after oxidation under 1000 °C for 1 h. However, the corrosion resistance of Zr-B-O nanocomposite films is negatively correlated with the power of ZrB2, which is related to the microstructure of the composite film.

Influences of sputtering power and annealing temperature on the structural and optical properties of Al2O3:CuO thin films fabricated by radio frequency magnetron sputtering technique

In the present study, we report the high visible to near infrared (NIR) transparent Al2O3:CuO thin films prepared using homemade high purity sputtering target by radio frequency magnetron sputtering technique with sputtering powers of 100, 200 and 300 W at room temperature and the prepared films were annealed at 300, 600 and 1000 °C for 1 h. X-ray diffraction analysis confirmed the amorphous formation of the deposited films. The obtained X-ray profiles of the sputtering target are refined using Rietveld refinement technique through the program package of general structure analysis system with EXPGUI interface. Optical study showed the sputtering power and annealing temperature persuaded red shift in absorption edge and as a consequence the shrinkage in optical band gap was observed. The obtained high average transparency of 87–96% in the wavelength range 400–1100 nm validates the transmittance of as-deposited and annealed Al2O3:CuO thin films is well extended into the near infrared region. The obtained optical transmittance and absorbance data were utilized to calculate various optical parameters.

Influence of sputtering power and Ar–N2 flow on the structure and optical properties of indium nitride films prepared by magnetron sputtering

ABSTRACTThis paper discusses the deposition of indium nitride (InN) thin films on Si (100) substrates by using pulsed DC magnetron sputtering. Effects of varying sputtering power and Ar–N2 flow ratio on the structural, morphological, and optical properties of indium nitride (InN) films were investigated. The structural characterization indicated nanocrystalline InN film with preferred orientation towards (101) plane that exhibited the optimum crystalline quality at 130 W and for 40:60 Ar–N2 ratio. The surface morphology of InN, as observed through FESEM, contained irregularly shaped nanocrystals with size that increases with higher sputtering power and Ar:N2 flow ratio. The optical properties of InN films were studied using ellipsometer at room temperature. The band gap of InN was decreased with the increase of sputtering power to 130 W, whereas an increase in the band gap was noticed with the increase of the Ar:N2 flow ratio.

Tailoring of TiO2 film crystal texture for higher photocatalysis efficiency

Abstract Nanocrystalline TiO2 thin films were deposited on borosilicate glass substrates using pulsed DC reactive magnetron sputtering in oxygen rich O2 Ar gas mixtures. The influence of sputtering power and argon‑oxygen gas flow ratio over crystallinity, crystal texture and surface morphology of the films was investigated. Interestingly, there was no correlation between the O/Ti concentration ratio in the films and their indirect band gap values. Based on experimentally observed band gap values and other properties of the films the model of the films consisting of nearly stoichiometric TiO2 crystals with a small fraction of weakly coordinated Ti impurities or amorphous low oxidation state titanium suboxide formations is proposed. Photocatalytic activity of the deposited films was analysed using inorganic markers and strong correlation between photocatalytic efficiency of TiO2 films with the (004) Crystalographic Preffered Orientation parameter was observed.

Variations of the microstructure and the optical and electrical properties with sputtering power for direct-current-magnetron-sputtered indium-doped CuO thin films at room temperature

Preparation of single-phased indium-doped copper oxide (CuO:In) thin films with high quality at low temperature is crucial for the commercial application of CuO-based solar cells and light-emitting devices. Herein, direct-current magnetron sputtering assisted with high sputtering power and reactive pressure technique was used to prepare monoclinic CuO:In thin films at room temperature. The influence of sputtering power (Pspu) on the microstructure and the optical and electrical properties of the films were studied. The roles of indium in the CuO:In thin films were also proposed. CuO:In thin films are single-phased and monoclinic in structure. The crystallization and the preferred 〈−111〉 orientation of the films were enhanced with increased Pspu. The red shift of the film absorption edge was due to the decrease and increase of the lattice strains along crystal axes a and b with Pspu, respectively. A conducting transition from p type to n type of the films at 100 W Pspu was closely related to the increased substitution of copper by indium. The p- and n-type conductions of the films were mainly due to the copper vacancies and interstitials oxygen and to the effective substitution of copper by indium in the films, respectively. Increased Pspu increased the free carrier concentration and decreased the mobility of the films. The free carrier concentration reached the maxima of 9.333 × 1018 /cm3 at 100 W Pspu, whereas the mobility reached the maxima of 23.38 cm2/Vs at 60 W Pspu.

Impact of Sputtering Power on Amorphous In–Al–Zn–O Films and Thin Film Transistors Prepared by RF Magnetron Sputtering

High-performance In–Al–Zn–O (IAZO) films and thin film transistors (TFTs) were fabricated using RF magnetron sputtering. The influence of sputtering power (90–250 W) on the film properties and device performance was investigated. All the IAZO films were in the amorphous state both before and after annealing, with a decrease in surface roughness observed with the increase of sputtering power. The Hall mobility of the annealed IAZO films degraded as the sputtering power increased. The highest Hall mobility of 63.6 cm2/ $\text{V}\cdot \text{s}$ and a proper carrier concentration of ${3.22} \times {10}^{{14}}$ /cm3 were obtained for the 90-W-deposited film. All the IAZO films exhibited high average visible transmittances (above 92%) and large optical bandgaps (4.10 ± 0.03 eV). The IAZO TFT prepared at 90 W had the best electrical properties with a high saturation mobility of 12.08 cm2/ $\text{V}\cdot \text{s}$ , a high ON–OFF current ratio of ${7.75} \times {10}^{{7}}$ , a low hysterisis of −0.19 V, and a low subthreshold swing (SS) of 0.55 V/dec.

Influence of sputtering power on structural, optical and electrical properties of CdTe thin films prepared by DC magnetron sputtering

The cadmium telluride (CdTe) thin films have been successfully deposited on glass substrates by direct-current (DC) magnetron sputtering method, and the structural, optical and electrical properties of samples were investigated in this paper. X-ray diffraction patterns revealed that all samples exhibited a preferred orientation along (111) plane with cubic phase, and the crystallite size was first increased from 13.6 to 42 nm and then decreased to 31 nm as the sputtering power increased from 10 to 80 W. AFM images showed that surface morphology of CdTe films was affected by the sputtering power and the particles in the films exhibited uniform distribution with obvious RMS roughness (25.9 nm) as the sputtering power was 40 W. Meanwhile, CdTe films appeared a higher transmission properties in the range of 850–1000 nm, and the band gap of films gradually decreased from 1.96 to 1.51 eV and then increased to 1.67 eV as the sputtering power constantly increased. Raman spectrum revealed that the peak at 140 cm−1 exhibited dominant among other peaks, associated to the E mode of Te. The current–voltage (I–V) curves indicated that the conductivity of CdTe films was strongly dependent on the sputtering power and the optimal electrical properties could be achieved at the sputtering power of 40 W.

The influence of sputtering power on the structural, morphological and optical properties of β-Ga2O3 thin films

In this work, Ga2O3 thin films were grown on Al2O3 (0001) substrate by radio frequency magnetron sputtering. The influence of sputtering power on crystalline structure, morphology, transmittance, band gap, and photoluminescence were investigated in detail. X-ray diffraction results showed that the β-Ga2O3 films were oriented along (2¯01) plane, and the crystalline quality improved with increasing sputtering power. Scanning electron microscope images revealed that the proportion of large-size grain increased with increasing sputtering power. The β-Ga2O3 films displayed very high transmittance close to 100% in visible region. Photoluminescence spectra showed that all the films exhibited intense blue and green emission centered at approximately 430 nm and 550 nm originated from the donor-acceptor pair recombination.

Influence of sputtering power on structural and magnetic properties of as-deposited, annealed and ERTA Co2FeSi films: A comparative study

We report the effect of sputtering power (200 W - 350 W) on the structural, topographical and magnetic properties of Co2FeSi (CFS) films deposited at ambient temperatures as compared to the films which were either annealed at 300 °C or were subjected to Electron beam Rapid Thermal Annealed (ERTA) treatment. The structural and morphological analyses reveal changes in their crystalline phases and particle sizes. All the as-deposited and annealed CFS films showed A2 phase crystal structure. Whereas the CFS film sputtered at 350 W followed by ERTA displayed the fully ordered L21 structure. The particles are spherical in shape and their sizes increased gradually with increase in the sputtering power of the as-deposited and annealed CFS films. However, ERTA CFS films had spherical as well as columnar (elongated) shaped grains and their grain sizes increased nonlinearly with sputtering power. M-H studies on as-deposited, annealed and ERTA CFS films show ferromagnetic responses. The comparatively stronger ferromagnetic response was observed for the ERTA samples with low saturation field which depends on the enrichment of fine crystallites in these films. This indicates that, apart from higher sputtering powers used for deposition of CFS films, ERTA process plays a significant role in the enhancement of their magnetic responses. 350 W ERTA film has the considerable saturation magnetization (∼816 emu/cc), coercivity (∼527 Oe) and a good squareness values at 100 K than at 300 K, which could originate from the spin wave excitation effect. Further, the optimized parameters to achieve a CFS film with good structural and magnetic properties are discussed from the perspective of spintronics.