Zr Films Research Articles

Influence of high work function ITO:Zr films for the barrier height modification in a-Si:H/c-Si heterojunction solar cells

We report the influence of magnetron sputtered zirconium-doped indium tin oxide (ITO:Zr) films with high mobility and work function on the heterojunction with intrinsic thin layer (HIT) solar cell. The addition of oxygen (O2) to argon (Ar) flow ratio during the deposition process improves the Hall mobility of the ITO:Zr films while the carrier concentration decreased. The small amount of oxygen resulted in an enhancement of work function while excess amount of O2 was not suitable for the electrical and surface properties of ITO:Zr films. The increase of O2/Ar flow ratio from 0% to 0.4% improved the work function from 5.03 to 5.13eV while the conductivity of ITO:Zr films remained about the same. The ITO:Zr films were employed as a front anti-reflection layer in a HIT solar cell and the best photo-voltage parameters were found to be Voc=710mV, Jsc=33.66mA/cm2, FF=72.4%, and η=17.31% for the O2/Ar flow ratio of 0.4%. The increase of ITO:Zr work function leads to an increase in open circuit voltage (Voc) and fill factor (FF) of the device. Therefore, the ITO:Zr films with high work function can be used to modify the front barrier height in the HIT solar cell.

Fabrication of Transparent Conductive Zinc Oxide Co-Doped with Fluorine and Zirconium Thin Solid Films by Ultrasonic Chemical Pyrolysis: Effects of Precursor Solution Aging and Substrate Temperature

Highly transparent, conducting zinc oxide [ZnO] thin films co-doped with fluorine and zirconium have been deposited on glass substrates by the ultrasonic chemical spraying technique. The effects of aging of the starting solution and substrate temperature on the structural, morphological, and electrical properties of the ZnO:F:Zr films have been studied. The resistivity of the films decreases with the aging time of the starting solution until the seventeenth day reaching a minimum of about 1.2×10−2 Ω cm and then increases. Though all the samples are of polycrystalline hexagonal wurtzite type and grow preferentially with (002) plane parallel to the substrate, their morphology depends strongly on the aging time of the reaction solution. The optical transmittance of all the films remained around 80% in the visible spectral range. These highly transparent, low resistive thin films are expected to be highly useful as transparent electrodes in the fabrication of thin film solar cells.

Magnetocrystalline Anisotropy and FMR Linewidth of Zr and Zn-Doped Ba-Hexaferrite Films Grown on MgO (111)

Ba M-type ferrite films of composition BaFe11Zn0.5Zr0.5O19 were grown on MgO (111) substrates by pulsed laser deposition. Both Zn and Zr divalent ions were introduced to reduce the magnetic anisotropy field to ~7.5 kOe, or 46% lower than the parent Ba M-type compound. Temperature dependence of magnetization over 25 to 350°C was investigated, indicating a Curie temperature of 320°C. Ferromagnetic resonance linewidth, as the peak-to-peak power absorption derivative at 9.55 GHz, was 120 Oe. The substituted sample had a K1 of ~0.920 × 106 erg/cm3. Such sample properties provide an attractive option for self-biased microwave devices applications operating at X (8-12 GHz) and Ku bands (12-18 GHz) as circulators and isolators.

Cu(Ge) alloy films with zirconium addition on barrierless Si for excellent property improvement

This paper reports the superior properties of Cu(Ge,Zr) films deposited by cosputtering on barrierless Si substrates. After being annealed, a self-forming ZrGex/Cu3Ge layer and a ZrOx (ZrSiyOx)/Cu3Ge layer, respectively, are formed during a sequence of solid-state reactions between the Cu(Ge,Zr) layer and adjacent layers and they could effectively hinder mutual diffusion between Cu and Si, presenting at the interface of the Cu/Cu(Ge,Zr)/Si film stacks. Leakage current and resistivity evaluations reveal the excellent thermal reliability of this Cu(Ge,Zr) film at temperatures up to 650 °C, suggesting its potential application in advanced barrierless Cu metallization. The mechanisms involved are analysed based on detailed characterization studies.

CONTROLLED REACTION ON INTERFACE OF Cu/Cu(Ge,Zr)/SiO 2 /Si MULTILAYER FILM AND ITS THERMAL STABILITY

A self–formation barrier method using CuX (X=Mn, Ti, Zr, Ru, RuN, WN, Ge, etc.) alloys with various concentration solutes has been extensively investigated to meet the requirements of low sheet resistivity, ultra–thin and high thermal stability for Cu metallization. However, intolerable reactions would take place at the interface of the Cu alloy layer and SiO2/Si layer before the processing temperature reaches high enough to drive the mass migration of alloy elements to interface. In fact, the reaction of Cu alloy layer with SiO2/Si layer is almost unavoidable due to that Cu diffuses very fast in Si substrate below 200 . Among those Cu–based alloys, CuGe alloy system has received particular * :r% 5/[ f 11075112 D 11005076, k/ #/r [ f 20100181120112 K 5j*:n C& )> lR f 2011GB110005 ! 9eJ$ v : 2013–05–24, 9e& $ v : 2013–07–29 +|v : {<r, i, 1987 n$, G/$ DOI: 10.3724/SP.J.1037.2013.00284 o 10 u z;qj : Cu/Cu(Ge, Zr)/SiO2/Si 5b [69 Vb yx#3 1265 attention because Cu can directly react with Ge below 150 and forms e–Cu3Ge films which exhibit a remarkable resistivity (5.5 μΩ·cm), and the Cu3Ge films also possess high oxidation resistance and interface bonding performance, so can be used as a good diffusion barrier for Cu as well. However, two major problems prevent it from being put into practice. The first is that the mutual diffusion occures between the Cu3Ge films and the Si substrates above 400 , and lead to a notable increase in resistivity. The second one is that the germanide film degrades morphologically at 350 . Therefore, according to the deficiencies existing in these Cu–based alloys, the main objective of the present research aims at taking advantage of the selective reaction characteristic of Cu, Ge and Zr elements to achieve a controlled interface reaction behavior of Cu/Cu(Ge, Zr)/SiO2/Si multilayer. The multilayer structure was characterized by FPPT, XRD, TEM, XPS and EDS. The results showed that the reaction sequence of the atoms in Cu(Ge, Zr) films and adjacent layers affected the thermal stability of Cu/Cu(Ge, Zr)/SiO2/Si multilayer structure. Under the temperature of 200 , Ge atoms reacted selectively with Cu film and produced e–Cu3Ge phase which exhibitted a remarkably low metallic resistivity, and the Cu3Ge phase could be used as a good diffusion barrier. With further increasing annealing temperature (above 450 ), Zr atoms precipitated at the interface or grain boundary of Cu3Ge layer and reacted with silicon oxide further to form stable and ultra–thin amorphous ZrOx/ZrSiyOx compounds. So the Cu3Ge layer combined with the amorphous ZrOx/ZrSiyOx compounds provided superior barrier properties in reducing Cu diffusion into Si at high annealed temperature.

Electron transfer dynamics of peptide‐derivatized RuII‐polypyridyl complexes on nanocrystalline metal oxide films

The performance of dye-sensitized solar and photoelectrochemical cells is strongly dependent on the electron transfer events at the electrode-sensitizer interface. Surface-bound peptides derivatized with chromophores have not been used in dye-sensitized solar and photoelectrochemical cells, but they have properties for these applications that could be advantageous by exploiting secondary structure and the attachment of multiple chromophores. In this manuscript, we have investigated structure-property relationships for three metallopeptide-based assemblies to solution and chemically bound to nanocrystalline MO(2) (M = Ti, Zr) films. A particular interest was exploring the influence of increasing separation distance between a common chromophore, [Ru(bpy)(2) (4-Me-4'-(NHCO)bpy)](2+) , and the underlying oxide substrate on excited and ground state electron transfer. Rates of Ru(II) oxidation to Ru(III) at the interface were measured by cyclic voltammetry on fluorine-doped tin oxide and cross-surface electron transfer on TiO(2) . Excited state injection by [Ru(III) (bpy)(2) (bpy(-) )](2+) was monitored by transient absorption and time-resolved emission. There are discernible trends in the electron transfer rate data with approximated, fully extended distances between the [Ru(bpy)(2) (4-Me-4'-(NHCO)bpy)](2+) sites and the interface. However, the distance dependences that are observed are smaller than anticipated, a result consistent with a lack of ordered secondary structure in the surface-bound peptide chains and a distribution of local orientations. For the surface-bound excited states, only a small fraction undergo quenching by electron transfer to TiO(2) , presumably from those oriented near the surface.

Microstructural, tribological and electrochemical corrosion studies on reactive DC magnetron sputtered zirconium nitride films with Zr interlayer on steel

Thin films of Zirconium Nitride (ZrN) were deposited by DC magnetron sputtering. The structure of the films was examined by X-ray diffraction and the crystallographic parameters were refined by Rietveld analysis. The columnar micro-structure was observed via cross-sectional SEM analysis. Defect induced, first order spectra were observed from Laser Raman studies. XPS showed the presence of Zr (N,O) ZrO2 phases on the surface of the film. The pitting corrosion was substantially reduced by the employment of Zr film as an interlayer. Corrosion tests revealed that ZrN films with a Zr interlayer exhibited clear passivation characteristics with considerably better corrosion resistance than the film without an interlayer.

Effects of applied voltage on the properties of anodic zirconia thin film on (100) silicon

The formation of thin zirconium dioxide (ZrO2) film by anodisation of 150nm thick zirconium (Zr) film on n-type silicon (Si) was investigated. Anodisation was performed in 1M NaOH (pH 14) at six different voltages ranging from 5V to 60V. All anodisation processes were done for 15min at room temperature in the bath with constant stirring. At lower voltages (5V and 10V), the anodised films are crystalline with high temperature cubic or tetragonal ZrO2 phases. For films anodised at voltages >20V, monoclinic ZrO2 appears along with the tetragonal or cubic ZrO2. The monoclinic phases exist mostly at the top part of the oxide with more tetragonal or cubic ZrO2 nearer to the oxide/substrate interface. For samples anodised above 40V, the oxide cracks severely and delaminates from the substrate with the degree of delamination more severe as the anodisation voltages were increased to 60V. At these voltages, the high temperature phases are no longer stabilised leading to the phase transformation to monoclinic ZrO2. Anodisation at 20V is therefore thought as an adequate voltage for the formation of relatively smooth oxide. This oxide has a root-mean-square value of 0.55nm, no cracks and reveals the highest breakdown voltage.

Preparation of ZnO:Zr Thin Films by Sputtering Zn:Zr Targets

Transparent conductive ZnO:Zr thin films with different thicknesses were fabricated on glass slides by DC reactive magnetron sputtering from Zn:Zr targets consisting of Zn disk and Zr metallic chips in Ar+O2mixture gas. X-ray diffraction, four-point probe measurements, UV–vis spectrophotometers and thin film thickness tester were employed to characterize the structure, electrical and optical properties of ZnO:Zr films, respectively. The experimental investigations indicate that film thickness has an important effect on the crystal structure, optical and electrical properties of the deposited films.

Cytocompatibility and haemocompatibility of Zr, ZrC and ZrCN films

The cytocompatibility and haemocompatibility of three zirconium based films, i.e. Zr, ZrC and ZrCN, deposited on NiTi shape memory alloy by magnetron sputtering are investigated and compared to those of electropolished NiTi shape memory alloy. The Zr(C,N) series films have deteriorated wettability but have positive effects on the blood compatibility and cytocompatibility of NiTi. Better haemolysis resistance and thromboresistant properties are observed. There are more living cells on the Zr(C,N) series films, and the cells show a higher relative growth rate value than those on the electropolished NiTi. The Zr(C,N) series films act as barrier layers and promote the proliferation of fibroblasts by blocking the leaching of toxic nickel ions from NiTi.

Au@MO2 (M= Ti, Zr, Si) Films by Ex Situ Incorporation Approach

Au NPs (average diameter similar to 20 nm) incorporated MO2 (M = Ti, Zr and Si) films on glass substrate were synthesized using an ex situ approach. Au NPs were first synthesized and then incorporated into the respective alkoxide derived sols with control of pH. The Au plasmon band was red-shifted in cases of Au@TiO2 and Au@ZrO2 films after annealing at 300 and 500 degrees C mainly due to the increase of refractive index (RI) with matrix crystallizations. Au@SiO2 film showed decrease in RI after annealing, and consequently the Au plasmon was blue-shifted. All heat-treated films appeared spot-free, optically homogeneous and colorful. The surface hardness of heat-treated Au@TiO2 and Au@ZrO2 films were >2H and 4H, respectively. The heat-treated Au@TiO2 and Au@ZrO2 films showed strong anatase TiO2 and cubic ZrO2 crystalline phases, respectively whereas in case of Au@SiO2, silica remained amorphous and porous.

Zr-based intermetallic diffusion barriers for stainless steel supported palladium membranes

► Oxidation of Zr thin film was completed by annealing in air at 500 °C. ► 0.1 μm thick ZrO 2 film prevented the metal migration at 400–600 °C. ► Zr and ZrN films required 0.5 μm thickness to prevent the metal migration at 600 °C. ► With 0.5 μm thickness, hydrogen permeation flux increased as Zr > ZrN > ZrO 2 . ► Zr, ZrN, ZrO 2 films also promoted hydrogen permeation. Electroless-plated palladium membranes were prepared on stainless steel supports with thin Zr, ZrO 2 and ZrN films as intermetallic diffusion barriers. DC magnetron sputtering, and reactive DC magnetron sputtering in the presence of a 2 sccm nitrogen flow rate, were used to deposit the Zr films or ZrN films, respectively. ZrO 2 films were obtained from oxidation of Zr films in air at 500 °C. The as-prepared films were characterized by X-ray diffraction (XRD), electro dispersive spectrometry (EDS) and scanning electron microscopy (SEM) for their phase structure, elemental composition and surface morphology, respectively. The presence of the Zr-based membrane barriers significantly reduced the intermetallic diffusion of Fe, Cr and Ni into the palladium membrane, as determined by SEM–EDS line scans, and increased the hydrogen permeation flux in the order of Zr < ZrN < ZrO 2 for the same 0.5 μm thickness. The results indicated that both ZrO 2 and ZrN thin (0.5 μm) films are promising intermetallic diffusion barriers, not only for preventing the metal migration into the palladium membrane but also in giving a high hydrogen permeance.

Thermally oxidized zirconium nanostructured films grown on Si substrates

AbstractZirconium thin films grown on Si substrates by a planar magnetron sputtering system were thermally oxidized at oxygen ambient within 523‐823 K resulting in zirconium oxide films with various stoichiometries. XRD analysis of the ex situ oxidized films revealed the phases at different oxidation temperatures. To achieve a reasonable fit between the experimental and SIMNRA simulated RBS spectra of the prepared samples; it was required to introduce a SiO2buffer layer in the simulated target between Si substrate and ZrO2 film. The presence of this intermediate SiO2 layer was confirmed by observation of SiO2 phase in the XRD patterns of all the thermally oxidized samples. Using RBS analysis data, the effect of oxidation temperature on the stoichiometry of zirconium oxide films and thickness of ZrOxand SiO2 films were investigated. XRD patterns of thermally oxidized Zr films also revealed that crystallization of zirconium oxide films was initiated at about 673 K and was almost completed at 823 K. Diffusion of oxygen atoms through surface layer was investigated and the effective activation energy for oxygen mass transport was estimated to be 1.75 eV using RBS data and Arrhenius relation. (© 2012 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

Influence of Ar/O2 Ratio on the Prpoperties of Transparent Conducting ZnO:Zr Films Deposited by DC Reactive Magnetron Sputtering

Transparent conducting ZnO:Zr thin films were deposited on glass substrates by DC reactive magnetron sputtering in Ar+O2ambience with different Ar/O2 ratios. The structural, electrical and optical properties of ZnO:Zr films were analyzed by X-ray diffraction, four-point probe measurements and UV–vis spectrophotometers. When Ar/O2ratio increases from 20:1 to 25:1, the resistivity significantly decreases because of the improvement of the crystallinity. However, with further increase in Ar/O2ratio, the crystallinity begins to deteriorate resulting in an increase in the resistivity. The films deposited at the optimum Ar/O2ratio of 25:1 have the minimum resistivity of 1.4×10-3Ω•cm and a high transmittance of above 92%.

Formation of Nanoparticles in Zr and Dy Doped YBCO MOD Superconducting Films

We study the formation mechanism of nanoparticles in thin films of the superconductor YBa2Cu3O7-δ(YBCO). We form the films by metal-organic deposition (MOD) on buffered, textured metal substrates. Through the addition of Dy or Zr salts to the precursor solution we precipitate (Y,Dy)2O3and BaZrO3nanoparticles, uniformly distributed through the film thickness. By quenching samples during the film growth, we show the nanoparticles form in the precursor layer before YBCO growth. The size of the nanoparticles was quantitatively analysed by TEM. We found that Zr doping produces smaller nanoparticles than Dy doping.

Band alignment and enhanced breakdown field of simultaneously oxidized and nitrided Zr film on Si

The band alignment of ZrO2/interfacial layer/Si structure fabricated by simultaneous oxidation and nitridation of sputtered Zr on Si in N2O at 700°C for different durations has been established by using X-ray photoelectron spectroscopy. Valence band offset of ZrO2/Si was found to be 4.75 eV, while the highest corresponding conduction offset of ZrO2/interfacial layer was found to be 3.40 eV; owing to the combination of relatively larger bandgaps, it enhanced electrical breakdown field to 13.6 MV/cm at 10-6 A/cm2.

The correlation between glass formation and hardness of the amorphous phase

We report a non-monotonous behavior of the hardness of amorphous Cu–Zr films as a function of composition, by applying a combinatorial deposition and nanoindentation method with unparalleled compositional resolution. Distinct peaks in hardness were identified at particular compositions to correlate well with the previously reported density peaks. Our results not only facilitate the discovery of new glass-forming alloys, but also raise the possibility of developing bulk metallic glasses with enhanced plasticity and/or ductility for engineering applications.

Comparative Study of the Properties between Transparent Conducting ZnO:Zr and ZnO:Al Films Deposited by DC Magnetron Sputtering

Transparent conducting zirconium-doped zinc oxide (ZnO:Zr) and aluminium-doped zinc oxide (ZnO:Al) thin films were deposited on glass substrates by direct current (DC) magnetron sputtering at room temperature. The crystallinity of ZnO:Zr and ZnO:Al thin films increases as the target-to-substrate distance decreases, and the crystallinity of ZnO:Zr films is found to be always better than that of ZnO:Al films prepared under the same deposition conditions. As the target-to-substrate distance decreases, the resistivity of both film types decreases greatly while the optical transmittance does not change much with the variation of the distance. When target-to-substrate distance is 4.1 cm, the lowest resistivity of 6.0×10-4 Ω·cm and 5.7×10-4 Ω·cm was obtained for ZnO:Zr and ZnO:Al films, respectively. The figure of merit arrived at a maximum value of 3.98×10-2Ω for ZnO:Zr films lower than 5×10-2 Ω for ZnO:Al films.

Study of microstructure and nanomechanical properties of Zr films prepared by pulsed magnetron sputtering

The present work studies the effect of substrate temperature on the growth characteristics of zirconium films prepared by pulsed magnetron sputtering. Formation of α-phase of zirconium was observed in the temperature range 300–873K. X-ray diffraction of Zr films revealed predominantly [001] texture. It is noticed that crystallite size increases with increasing substrate temperature. Hexagonal shaped crystallites seem to grow along the surface normal of the substrate for the films deposited at 773K. Nanoindentation measurements showed that the hardness of the films is in the range 6–10GPa. The scratch test indicated that the films deposited at higher substrate temperatures had excellent bonding with the substrate and no significant critical failure was noticed up to an applied load of 20N.

The effect of oxidation temperature on the nano crystalline structure of ZrO2 films deposited on silicon and glass substrates

AbstractZirconium oxide (ZrO2) films have been prepared by using ex situ thermal oxidation of sputtered Zr films on glass and silicon substrates. XRD patterns show that a highly monoclinic (111) preferential orientation of ZrO2 phase can be formed with increasing the oxidation temperature. According to XRD patterns in all thermal oxidized samples silicon oxide phase is present as interfacial layer at the Zr (ZrO2) / Si (glass) interface. In the case of silicon substrates, crystallite sizes obtained from ZrO2 peak with higher intensity reveal an increase with substrate temperature. AFM measurement shows on the whole a decrease of average surface roughness with oxidation temperature. The electrical property of the prepared films is investigated by means of four point probe measurement. An abrupt increase of sheet resistivity occurs when the crystallinity of ZrO2 phase enhances at higher temperature. (© 2011 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)