Use of the magnetron-sputtering technique for the control of the properties of indium tin oxide thin films

Indium tin oxide films were made with their stoichiometry controlled to give optimum electrical and optical properties. They were deposited by d.c. magnetron sputtering on glass substrates at room temperature. The mechanical properties of these films were also studied. The initial experiments show the dependence of resistivity on film thickness. The controlled processes gave a resistivity of about 10⁻⁵ Ωm and visible transmission of about 85%. The performance of ITO films can be increased by annealing the films in argon ambient.     

The effect of gallium concentration and substrate temperature on the properties of Ga-Doped ZnO thin films sputtered from powder compacted target

Gallium-doped zinc oxide films with an average thickness of 300 nm were grown on corning glass 1737 substrate by radio frequency (RF) magnetron sputtering using powder compacted target with Ga concentrations of 0 wt.%, 2 wt.%, and 4 wt.%. The structural, optical and electrical properties of the films were investigated. During sputtering, deposition temperature was varied from room temperature to 200°C in 50°C intervals. All films were polycrystalline, having a preferred growth orientation with thec-axis perpendicular to the substrate. By increasing Ga concentration and substrate temperature, the peak height corresponding to the (002) plane was significantly increased. Columnar structure was clearly observed in the film deposited with a Ga concentration of 4 wt.% regardless of deposition temperature. The lowest resistivity achieved was 4×10⁻³ Ωcm at a Ga concentration of 4 wt.% grown at 200°C. All doped films showed an overall transmittance in the visible spectra of above 90%.     

Preparation and properties of tungsten-doped indium oxide thin films

Tungsten-doped indium oxide (IWO) thin films were deposited on glass substrate by DC reactive magnetron sputtering. The effects of sputtering power and growth temperature on the structure, surface morphology, optical and electrical properties of IWO thin films were investigated. The thickness and surface morphology of the films are both closely dependent on the sputtering power and the substrate temperature. The transparency of the films decreases with the increase of the sputtering power but is not seriously influenced by substrate temperature. All the IWO thin film samples have high transmittance in near-infrared spectral range. With either the sputtering power or the growth temperature increases, the resistivity of the film decreases at the beginning and increases after the optimum parameters. The as-deposited IWO films with minimum resistivity of 6. 4× 10-4 Ω·cm were obtained at a growth temperature of 225 ℃ and sputtering power of 40 W, with carrier mobility of 33. 0 cm2· V-1·s-1 and carrier concentration of 2. 8× 1020 cm-3 and the average transmittance of about 81％ in near-infrared region and about 87％ in visible region.     

Preparation and characterization of ZnO/Cu/ZnO transparent conductive films

ZnO/Cu/ZnO transparent conductive thin films were prepared by RF sputtering deposition of ZnO target and DC sputtering deposition of Cu target on n-type (001) Si and glass substrates at room temperature. The morphology, structure, optical, and electrical properties of the multilayer films were characterized by field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), UV/Vis spectrophotometer, and Hall effect measurement system. The influence of Cu layer thickness and the oxygen pressure in sputtering atmosphere on the film properties were studied. ZnO/Cu/ZnO transparent conductive film fabricated in pure Ar atmosphere with 10 nm Cu layer thickness has the best performance: resistivity of 2.3×10-4 Ω·cm, carrier concentration of 6.44×1016cm-2 , mobility of 4.51cm2·(V·s)-1 , and acceptable average transmittance of 80 % in the visible range. The transmittance and conductivity of the films fabricated with oxygen are lower than those of the films fabricated without oxygen, which indicates that oxygen atmosphere does not improve the optical and electrical properties of ZnO/Cu/ ZnO films.     

CuS-based thin films for architectural glazing applications produced by co-evaporation: Morphology, optical and electrical properties

Copper sulphide thin films in the 90–300 nm thickness range have been deposited on soda–lime glass substrates by thermal co-evaporation of Cu and S. Depending on the film thickness, the optical transmittance in the visible region is of about 50% for the thinnest film and 19% for the thickest film, with the corresponding near-infrared transmittance dropping from 11% to near-zero at 2500 nm as the film thickness increases from 90 to 300 nm. A resistivity of ρ ~ 10^− 4 Ω cm has been obtained for the films. The optoelectronic properties of the films remained practically unchanged after one year stored under laboratory ambient. The optical properties obtained for selected CuS-based films make them suitable for their use as effective solar control glazings in warm climates.     

A comparative study of nanocrystalline Cu film deposited using anodic vacuum arc and dc magnetron sputtering

A comparative study of structural, electrical and thermoelectric properties of nanocrystalline copper thin films deposited using anodic vacuum arc plasma deposition technique and dc-magnetron sputtering is presented. The crystallographic texture and structural evolution of these films are investigated as a function of thickness within a range of 30 to 230 nm using XRD and SEM. AVA deposited Cu films possess smaller grains with a lesser degree of crystallinity than dc-sputtered ones. Electrical resistivity, temperature coefficient of resistance and thermoelectric power of both as-deposited and annealed Cu films of AVA and dc-magnetron sputtering is measured and their dependence on the film thickness is investigated. AVA deposited Cu films having thickness less than 100 nm show much higher resistivity than dc-sputtered ones. AVA deposited Cu films possess lower temperature coefficient of resistance values than dc-sputtered ones. The observed thickness dependence of thermoelectric power is larger in AVA deposited Cu films than in dc-sputtered ones. These electrical measurements reveal that AVA deposited Cu films possess more vacancies than dc-sputtered ones.     

Effect of annealing temperature on optical band-gap of amorphous indium zinc oxide film

The effect of annealing temperature on the electrical and optical properties of indium zinc oxide (IZO) (In₂O₃:ZnO = 90:10 wt.%) thin films has been investigated. The IZO thin films were deposited on glass substrates by radio frequency magnetron sputtering and then subjected to annealing in a mixed ambient of air and oxygen at 100, 200 and 300 °C. All the IZO films were found to have amorphous structure. With the increase of the annealing temperature, the carrier concentration decreased and the resistivity increased. The average transmittance of IZO thin films decreased slightly with annealing temperature. Interestingly, a systematic reduction of the optical band-gap from 3.79 eV to 3.67 eV was observed with annealing temperature. The change in optical band-gap was observed to be caused predominantly by Burstein-Moss band-gap widening effect suggesting unusual absence of band narrowing effect. The effects on optical and electrical properties of IZO films have been discussed in detail.     

Fabrication and characterization of ITO thin films on heat-resistant transparent flexible clay films

Transparent conductive indium tin oxide (ITO) thin films were deposited on transparent flexible clay films with heat resistant and high gas barrier properties by rf magnetron sputtering. The electrical, structural, and optical properties of these films were examined as a function of deposition temperature. A lowest resistivity of 4.2 × 10^− 4 Ωcm and an average transmittance more than 90% in the visible region were obtained for the ITO thin films fabricated at deposition temperatures more than 300 °C. It was found that ITO thin films with low resistivity and high transparency can be achieved on transparent flexible clay film using conventional rf magnetron sputtering at high temperature, those characteristics are comparable to those of ITO thin films deposited on a glass substrate.     

Structural, morphological and electrical properties of spray deposited nano-crystalline CeO2 thin films

Nanocrystalline, uniform, dense, and adherent cerium oxide (CeO₂) thin films have been successfully deposited by a simple and cost effective spray pyrolysis technique. CeO₂ films were deposited at low substrate and annealing temperatures of 350 °C and 500 °C, respectively. Films were characterized by differential thermal analysis, X-ray diffraction, scanning electron microscopy, atomic force microscopy; two probe resistivity method and impedance spectroscopy. X-ray diffraction analysis revealed the formation of single phase, well crystalline thin films with cubic fluorite structure. Crystallite size was found to be in the range of 10-15 nm. AFM showed formation of smooth films with morphological grain size 27 nm. Films were found to be highly resistive with room temperature resistivity of the order of 10⁷ Ω cm. Activation energy was calculated and found to be 0.78 eV. The deposited film showed high oxygen ion conductivity of 5.94 × 10⁻³ S cm⁻¹ at 350 °C. Thus, the deposited material shows a potential application in intermediate temperature solid oxide fuel cells (IT-SOFC) and might be useful for μ-SOFC and industrial catalyst applications.     

Preparation and characterization of non-evaporable porous Ti-Zr-V getter films

Highly porous TiZrV film getters on (100) silicon substrates have been successfully grown by the glancing angle dc magnetron sputtering method. The glancing angle is defined as the angle between the surface normal to the substrate and the surface normal to the target. The main deposition parameters that produce the porous TiZrV films are the pressure of sputtering gas Ar and glancing angle at room temperature. The larger the glancing angle is, the higher the porosity and specific surface area of the TiZrV films are. The specific surface area of the dense and porous TiZrV films is 2 m²/g and 13 m²/g, respectively. The diameter of columnar width and inter-distance between the columnar crystals of the porous film are 200 nm and 50 nm, respectively. The columnar width of dense TiZrV films is about 100 nm. The porous TiZrV films have a larger capability to absorb oxygen than that of the dense TiZrV films.     

Characteristics of ITO films deposited on a PET substrate under various deposition conditions

ITO films, with a thickness of 150 nm to 160 nm, were deposited on an unheated hard coated PET substrate or non-alkali glass substrate via dc magnetron sputtering. Depositions were carried out under the following various conditions: total gas pressure (P_tot), dc sputtering power, target — substrate (T-S) distance, and O₂ or H₂ addition ratio. The ITO coated on the PET substrate showed relatively lower resistivity than that of the ITO coated on a glass substrate. Relatively small changes in the resistance (ΔR/R₀=0.4) of the films were obtained for each deposition condition for the ITO/PET deposited under a sputtering power of 70 W, P_tot of 0.5 Pa, and T-S of 50 mm. It has been confirmed that the results of the electrical property showed concurrence with the results of the bending test. Specifically, the films that have a good electrical property showed only a small change in resistance to the increasing cycle number for each deposition condition. Therefore, it can be assumed that the increased resistance of the ITO films could be due to the formation of micro defects such as micro-cracks and the micro detachment of the ITO film from the flexible PET substrate.     

Optical and electrical properties of TiO2/Au/TiO2 multilayer coatings in large area deposition at room temperature

TiO2/Au/TiO2 multilayer thin films were deposited at polymer substrate at room temperature using dc (direct current) magnetron sputtering method.By varying the thickness of each layer,the optical and electrical properties of the TiO2/Au/TiO2 multilayer films can be tailored to suit different applications.The thickness and optical properties of the Au layer and the quality of the Au-dielectric interfaces are critical for the electrical and optical performance of the Au-dielectric multilayer thin films.At the thickness of 8 nm,the Au layer forms a continuous structure having the lowest resistivity and it must be thin for high transmittance.The multilayer stack can be optimized to have a sheet resistance of 6 Ω/sq.at a transmittance over 80% at 680 nm in wavelength.The peak transmittance shifts towards the long wavelength region when the thickness of the two TiO2 (upper and lower) layers increases.When the film thickness of the two TiO2 film is 45 nm,a high transmittance value is obtained for the entire visible light wavelength region.     

AC powered reactive magnetron deposition of indium tin oxide (ITO) films from a metallic target

Transparent highly conductive indium tin oxide (ITO) films for low cost applications were deposited by a reactive dual magnetron sputter process using metallic targets. The magnetrons were equipped with rectangular (130 × 400 mm²) In:Sn targets (90 wt.% In/10 wt.% Sn). A sine wave power supply was used at a frequency of about 70 kHz. All experiments were done in the transition mode at a constant argon flow of 40 sccm and an oxygen flow varied between 35 and 70 sccm. The total pressure was kept constant at 0.4 Pa.The films were deposited onto silicon and float glass substrates which were either moved in an oscillatory manner (dynamic deposition) or fixed in front of the targets (static mode) during deposition. A dynamic deposition rate of about 100 nm × m/min was obtained at an average power of 2 kW/cathode. The film thickness was adjusted to 500 nm. At an optimised Ar/O₂ gas flow ratio of 0.6 we found an electrical resistivity as low as 1.2 × 10^− 3 Ω cm. The refractive index of these films was about 2.05 indicating a dense film structure, while the optical absorption of k = 10^− 2 qualifies these ITO films for many low cost applications. Moreover, the film structure and texture were investigated by XRD methods.Applying a static deposition we have achieved a lower electrical resistivity with a minimum value of 6 × 10^− 4 Ω cm. In this case, the resistivity and the transparency, respectively, were not constant over the substrate but depend on the lateral position in front of the target. To explain this inhomogeneity we have performed spatially resolved deposition rate and Langmuir probe measurements and related their results to film structure and properties. In order to improve the film properties at dynamic deposition the growth conditions have to be homogenised at all substrate positions.     

Thin films of thermoelectric compound Mg2Sn deposited by co-sputtering assisted by multi-dipolar microwave plasma

Magnesium stannide (Mg₂Sn) thin films doped with Ag intended for thermoelectric applications are deposited on both silicon and glass substrates at room temperature by plasma assisted co-sputtering. Characterization by scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction confirms the formation of fine-grained polycrystalline thin films with thickness of 1-3 μm. Stoichiometry, microstructure and crystal structure of thin films are found to vary with target biasing and the distance from targets to substrate. Measurements of electrical resistivity and Seebeck coefficient at room temperature show the maximum power factor of ∼5.0 × 10⁻³ W K⁻² m⁻¹ for stoichiometric Mg₂Sn thin films doped with ∼1 at.% Ag.     

Fabricating TiO2 Photocatalysts by rf Reactive Magnetron Sputtering at Varied Oxygen Partial Pressures

Titanium dioxide (TiO₂) thin films were fabricated onto non-alkali glass substrates by rf reactive magnetron sputtering at room temperature using Ti-metal target at varied oxygen partial pressure [O₂/(Ar + O₂)]. The sputtering deposition was performed under an rf power of 200 W. The target to substrate distance was kept at 80 mm, and the total gas pressure was 10 mTorr after 2 h of deposition. It was found that the crystalline structure, surface morphology, and photocatalytic activities of the TiO₂ thin films were affected by the oxygen partial pressure during deposition. The XRD patterns exhibited a broad-hump shape indicating the amorphous structure of TiO₂ thin films. The thin films deposited at a relatively high value of oxygen partial pressure (70%) had a good photo-induced decomposition of methylene blue (MB), photo-induced hydrophilicity, and had a small grain size.     

Effects of processing parameters on the properties of tantalum nitride thin films deposited by reactive sputtering

The effects of processing parameters on the properties of tantalum nitride thin films deposited by radio frequency reactive sputtering have been investigated. The influence of the N₂ partial and (Ar + N₂) total gas pressures as well as the sputtering power on the microstructure and electrical properties is reported. Rising the N₂ partial pressure, from 2 to 10.7%, induces a change in the composition of the δ-TaN phase, from TaN to TaN_1.13. This composition change is associated with a drastic increase of the electrical resistivity over a 7.3% N₂ partial pressure. The total gas pressure is revealed to strongly affect the film microstructure since a variation in both composition and grain size is observed when the gas pressure rises from 6.8 to 24.6 Pa. When the sputtering power varied between 50 and 110 W, an increase of the grain size related to a decrease of the electrical resistivity is observed.     

射频反应磁控溅射法制备ZnO:Al透明导电薄膜的光电性能

室温下采用射频(RF)反应磁控溅射技术在玻璃衬底上沉积具有(002)择优取向的透明导电Al掺杂ZnO(AZO)薄膜。XRD结果表明,制备的AZO薄膜为多晶,具有c轴择优取向。退火处理能提高其结晶度。在Al靶射频功率为40W,ZnO靶射频功率为250W,氩气流量为15mL/min的条件下,获得200nm厚的薄膜电阻率约3.8×10-3?·cm,在可见光范围内有很好的光透过率。     

EFFECT OF Ar PRESSURE ON STRUCTURAL AND ELECTRICAL PROPERTIES OF Cu FILMS DEPOSITED ON GLASS BY DC MAGNETRON SPUTTERING

Cu films with thickness of 630-1300nm were deposited on glass substrates without heating by DC magnetron sputtering in pure Ar gas. Ar pressure was controlled to 0.5, 1.0 and 1.5Pa respectively. The target voltage was fixed at 500V but the target current increased from 200 to 1150mA with Ar pressure increasing. X-ray diffrac-tion, scanning electron microscopy and atomic force microscopy were used to observe the structural characterization of the films. The resistivity of the films was measured using four-point probe technique. At all the Ar pressures, the Cu films have mixture crystalline orientations of [111], [200] and [220] in the direction of the film growth. The film deposited at lower pressure shows more [111] orientation while that deposited at higher pressure has more [220] orientation. The amount of larger grains in the film prepared at 0.5Pa Ar pressure is slightly less than that prepared at 1.0Pa and 1.5Pa Ar pressures. The resistivities of the films prepared at three different Ar pressures re     

Effects of substrate temperature and annealing on the anisotropic magnetoresistive property of NiFe films

Ni83Fei7 films with a thickness of about 100 ran were deposited on thermal oxidized silicon substrates at ambient temperature, 240, 350, and 410℃ by DC magnetron sputtering. The deposition rate was about 0.11 nm/s. The as-deposited films were annealed at 450, 550, and 650℃, respectively, in a vacuum lower than 3 x 10-3 Pa for 1 h. The Ni83Fei7 films mainly grow with a crystalline orientation of [111] in the direction of the film growth. With the annealing temperature increasing, the [111] orientation enhances. For films deposited at all four different temperatures, the significant improvement on anisotropic magnetoresistance occurs at the annealing temperature higher than 550℃. But for films deposited at ambient temperatures and 240 ℃, the anisotropic magnetoresistance can only rise to about 1% after 650 ℃ annealing. For films deposited at 350℃ and 410℃, the anisotropic magnetoresistance rises to about 3.8% after 650℃ annealing. The atomic force microscopy (AFM) observation shows a significant i     

The Electrical Characterization and NIR Absorption of ITO Film under Different Sputtering Time

Indium-tin-oxide(ITO)films with different sputtering time have been prepared by dc magnetron sputtering method on PET substrate at room temperature.The film structure,thickness,electrical and optical properties are investigated through XRD,SEM,van der Pauw method and FTIR,respectively.The XRD results indicate that all the films are amorphous structure.With the increase of sputtering time,resistivity and transmittance decrease simultaneously.However the absorption gets stronger,especially in near-infrared light region.Through Drude model the plasma frequency is calculated and the calculation result is pretty consistent with films deposited at 60 and 90 min.