Showing papers on "Sputter deposition published in 2005"
TL;DR: The present status and prospects for further development of polycrystalline or amorphous transparent conducting oxide (TCO) semiconductors used for practical thin-film transparent electrode applications are presented in this paper.
Abstract: The present status and prospects for further development of polycrystalline or amorphous transparent conducting oxide (TCO) semiconductors used for practical thin-film transparent electrode applications are presented in this paper. The important TCO semiconductors are impurity-doped ZnO, In2O3 and SnO2 as well as multicomponent oxides consisting of combinations of ZnO, In2O3 and SnO2, including some ternary compounds existing in their systems. Development of these and other TCO semiconductors is important because the expanding need for transparent electrodes for optoelectronic device applications is jeopardizing the availability of indium-tin-oxide (ITO), whose main constituent, indium, is a very expensive and scarce material. Al- and Ga-doped ZnO (AZO and GZO) semiconductors are promising as alternatives to ITO for thin-film transparent electrode applications. In particular, AZO thin films, with a low resistivity of the order of 10−5 Ω cm and source materials that are inexpensive and non-toxic, are the best candidates. However, further development of the deposition techniques, such as magnetron sputtering or vacuum arc plasma evaporation, as well as of the targets is required to enable the preparation of AZO and GZO films on large area substrates with a high deposition rate.
1,959 citations
TL;DR: In this article, transparent thin-film transistors (TTFTs) with an amorphous zinc tin oxide channel layer formed via rf magnetron sputter deposition are demonstrated.
Abstract: Transparent thin-film transistors (TTFTs) with an amorphous zinc tin oxide channel layer formed via rf magnetron sputter deposition are demonstrated. Field-effect mobilities of 5–15 and 20–50cm2V−1s−1 are obtained for devices post-deposition annealed at 300 and 600°C, respectively. TTFTs processed at 300 and 600°C yield devices with turn-on voltage of 0–15 and −5–5V, respectively. Under both processing conditions, a drain current on-to-off ratio greater than 107 is obtained. Zinc tin oxide is one example of a new class of high performance TTFT channel materials involving amorphous oxides composed of heavy-metal cations with (n−1)d10ns0 (n⩾4) electronic configurations.
778 citations
TL;DR: In this article, a real-time monitoring of the anodization current, at a fixed potential, is used to controllably eliminate the Ti layer underneath the titanium oxide nanotubes without disturbing the architecture.
Abstract: Titanium thin films, 400 nm to 1000 nm thick, fabricated by radio frequency (rf) sputter deposition are anodized in an electrolyte containing acetic acid and hydrofluoric acid to form optically transparent films of highly ordered titania nanotube arrays Real-time monitoring of the anodization current, at a fixed potential, is used to controllably eliminate the Ti layer underneath the titanium oxide nanotube array without disturbing the architecture Fabrication variables critical to achieving the transparent nanotube-array film include annealing temperature of the anodized, initially amorphous nanotube array and Ti-film sputter deposition variables, including rate, film thickness, and substrate temperature Structural investigations on the transparent nanotube arrays reveal only the presence of the anatase phase even after annealing at 500 °C In contrast, both rutile and anatase phases were observed in films with a metal layer underneath the nanotubes and annealed in an oxygen ambient above 430 °C Rutile growth occurs at the nanotube–metal interface as metal oxidation takes place during annealing The average refractive index of the transparent nanotube-array film is found to be 166 in the UV-vis range, with a calculated porosity of 67 %; the bandgap is determined as 334 eV, with a bandgap tail extending to 24 eV
472 citations
TL;DR: A critical review of the present state of the knowledge in the field of dc reactive magnetron sputtering of compound films is given in this article, where the conditions under which oxides are reactively sputtered with high deposition rates aD oxide achieving up to approximately 77% of that of a pure metal aD Me.
346 citations
TL;DR: In this paper, both pulsed dc and mid-frequency ac power was used to prevent arcing during reactive sputtering of insulating films. But the results showed that the results were not optimal.
337 citations
TL;DR: In this paper, a hybrid sputtering system with two sputter sources and two effusion cells is used to fabricate Cu 2 ZnSnS 4 thin films by sequential deposition of metal elements and annealing in S flux, varying the substrate temperature.
314 citations
TL;DR: In this article, single-phase vanadium dioxide (VO2) thin films have been grown on Si3N4∕Si substrates by means of a well-controlled magnetron sputtering process.
Abstract: Single-phase vanadium dioxide (VO2) thin films have been grown on Si3N4∕Si substrates by means of a well-controlled magnetron sputtering process. The deposited VO2 films were found to exhibit a semiconductor-to-metal transition (SMT) at ∼69°C with a resistivity change as high as 3.2 decades. A direct and clear-cut correlation is established between the SMT characteristics (both amplitude and abruptness of the transition) of the VO2 films and their crystallite size.
299 citations
TL;DR: In this article, Nitrogen-doped films of ZnO grown by two methods, metalorganic chemical vapor deposition (MOCVD) and reactive sputtering, were studied with x-ray and ultraviolet photoelectron spectroscopy (XPS and UPS).
Abstract: Nitrogen-doped films of ZnO grown by two methods, metalorganic chemical vapor deposition (MOCVD) and reactive sputtering, were studied with x-ray and ultraviolet photoelectron spectroscopy (XPS and UPS). Systematic differences in the N chemical states were observed between films grown by sputtering and MOCVD: only two N chemical states were observed in films grown by reactive sputtering, whereas four N chemical states were observed in MOCVD films. To aid in the assignment of the N chemical states, photoemission data from the polycrystalline films were compared with data taken on N2+-implanted Zn metal and N2+-implanted ZnO. High-resolution core level spectra of the N1s region indicated that nitrogen can occupy at least four different chemical environments in ZnO; these include the NO acceptor, the double donor (N2)O, and two carbon–nitrogen species. Valence band spectra indicate that the Fermi energy of all films studied was near the conduction band minimum, implying that the films remained n-type after n...
278 citations
TL;DR: In this paper, a transition from a columnar to a glassy microstructure has been observed in the nanocomposite coatings with increasing substrate bias or carbon content.
267 citations
TL;DR: In this paper, a source for producing size-selected nanoclusters based on the combination of radio frequency magnetron plasma sputtering and gas condensation is presented, which can produce clusters in the size range from 2 up to at least 70,000 atoms, depending on the target material, with a constant mass (M) resolution (M∕ΔM∼25) at an intensity that produces atomic monolayer coverage in as little as a few minutes.
Abstract: We report on a source for producing size-selected nanoclusters based on the combination of radio frequency magnetron plasma sputtering and gas condensation. The use of plasma sputtering to vaporize a target is applicable to a large range of materials; Ag, Au, Cu, and Si have been attempted to date. The source, combined with a time-of-flight mass filter, can produce clusters in the size range from 2 up to at least 70 000 atoms, depending on the target material, with a constant mass (M) resolution (M∕ΔM∼25) at an intensity that produces atomic monolayer coverage in as little as a few minutes. The source is also attached to an ultrahigh vacuum analysis chamber, which allows in situ surface chemical and structural analysis. Examples of cluster deposition experiments with the source are also presented.
262 citations
TL;DR: In this paper, a simple pathways model has been developed to explain the experimental results of high power pulsed magnetron sputtering, which can generate a dense plasma with high target material ion content, but reported deposition rates are significantly lower than for dc or midfrequency ac sputtering at the same average power.
Abstract: The potential of high power pulsed magnetron sputtering (HPPMS) has created growing interest, because it can generate a dense plasma with high target material ion content. However, reported deposition rates are significantly lower than for dc or midfrequency ac sputtering at the same average power in most cases. The fraction of target material arriving at the workpiece, which is ionized, ranges from 5% to 70% as reported so far by workers in the field, even though optical emission spectroscopy suggests a highly metallic plasma. A simple pathways model has been developed to explain these experimental results. In addition, evaluation of the model for various interesting materials suggests target material characteristics which are desirable in order to achieve higher deposition rates and a greater ionized fraction of target material reaching the substrate. The model will be presented, with representative characteristic results and implications on HPPMS processes. In addition, insights from approximate model equations will be presented.
TL;DR: Flexible transistors were fabricated by sputter deposition of zinc tin oxide (ZTO) onto plasma-enhanced chemical vapor deposition gate dielectrics formed on flexible polyimide substrates with a blanket aluminum gate electrode, and they exhibited high on-currents of 1mA, on/off ratios of 106, subthreshold voltage slopes of 1.6V/decade, turn-on voltages of −17V, and mobilities of 14cm2V−1s−1.
Abstract: Flexible transistors were fabricated by sputter deposition of zinc tin oxide (ZTO) onto plasma-enhanced chemical vapor deposition gate dielectrics formed on flexible polyimide substrates with a blanket aluminum gate electrode. The flexible transistors exhibited high on-currents of 1mA, on/off ratios of 106, subthreshold voltage slopes of 1.6V/decade, turn-on voltages of −17V, and mobilities of 14cm2V−1s−1. Capacitance measurements indicate that the threshold voltage and subthreshold slope are primarily influenced by residual doping in the ZTO rather than by defects at the semiconductor/dielectric interface, and are useful for assessing contact resistance.
TL;DR: In this article, the structural, optical and electrical properties of NiO thin films were investigated using X-ray diffraction (XRD), visible spectrum and Hall effect measurements, and the dependences of film properties on substrate temperature, crystalline structure and natural aging effect were studied.
Abstract: Nickel oxide (NiO) thin films were deposited by RF magnetron sputtering process at different RF powers and substrate temperatures in a pure oxygen atmosphere. The structural, optical and electrical properties of NiO films were investigated using X-ray diffraction (XRD), visible spectrum and Hall effect measurements. The dependences of film properties on substrate temperature, crystalline structure and natural aging effect were studied. The results show that the resistivity increases as sputtering power increases from 100 to 200 W at constant temperature. The lowest resistivity and Hall coefficient obtained are 16.7 V cm and 1.99 cm 3 /C, respectively, as the sputtering power is 100 Wand substrate temperature is 3508. The highest carrier concentration obtained is 3.1310 18 cm 3 as the sputtering power is 100 Wand substrate temperature is 3508. The crystal structure was analyzed by X-ray diffraction method. The preferred orientation of NiO film changes from (111) to (200) when the substrate temperature varies from unheated condition to 3508. Electrical properties of NiO films were unstable and show a natural aging effect. Resistivity of NiO films increases as the time of natural aging increases. Under the substrate-unheated condition, the transmittance of as-deposited samples is lower compared to the film prepared at substrate temperature of 350 8C. The change in transmittance may be due to the microstructural change in the material. It is suggested that the sputtering power affects the preferred orientation of NiO film. Higher substrate temperature induces larger grain size and more perfect crystalline structure, which lead to low resistivity of NiO film. D 2004 Published by Elsevier B.V.
TL;DR: In this paper, the photoluminescence (PL) spectra revealed an acceptor bound exciton peak at 3.355 eV and a conduction band to the acceptor transition caused by a phosphorus related level at 3,310 eV.
Abstract: Phosphorus-doped p-type ZnO thin films were grown on sapphire by radio-frequency magnetron sputtering. The photoluminescence (PL) spectra revealed an acceptor bound exciton peak at 3.355 eV and a conduction band to the acceptor transition caused by a phosphorus related level at 3.310 eV. A study of the dependence of the excitation laser power density and temperature on the characteristics of the PL spectra suggests that the emission lines at 3.310 and 3.241 eV can be attributed to a conduction band to the phosphorus-related acceptor transition and a donor to the acceptor pair transition, respectively. The acceptor energy level of the phosphorus dopant was estimated to be located 127 meV above the valence band.
TL;DR: In this article, the ion to neutral ratio of the sputtered material have been studied for high power pulsed magnetron sputtering and compared with a continuous direct current discharge using the same experimental setup except for the power source.
Abstract: The ion to neutral ratio of the sputtered material have been studied for high power pulsed magnetron sputtering and compared with a continuous direct current (dc) discharge using the same experimental setup except for the power source. Optical emission spectroscopy (OES) was used to study the optical emission from the plasma through a side window. The emission was shown to be dominated by emission from metal ions. The distribution of metal ionized states clearly differed from the distribution of excited states, and we suggest the presence of a hot dense plasma surrounded by a cooler plasma. Sputtered material was ionized close to the target and transported into a cooler plasma region where the emission was also recorded. Assuming a Maxwell–Boltzmann distribution of excited states the emission from the plasma was quantified. This showed that the ionic contribution to the recorded spectrum was over 90% for high pulse powers. Even at relatively low applied pulse powers, the recorded spectra were dominated by emission from ions. OES analysis of the discharge in a continuous dc magnetron discharge was also made, which demonstrated much lower ionization.
TL;DR: In this article, the authors synthesized Ta thin films on Si substrates placed along a wall of a 2 cm-deep and 1 cm-wide trench, using both a mostly neutral Ta flux by conventional dc magnetron sputtering (dcMS) and a mostly ionized Ta flux (HPPMS) by high-power pulsed magnetron stuttering.
Abstract: We have synthesized Ta thin films on Si substrates placed along a wall of a 2-cm-deep and 1-cm-wide trench, using both a mostly neutral Ta flux by conventional dc magnetron sputtering (dcMS) and a mostly ionized Ta flux by high-power pulsed magnetron sputtering (HPPMS). Structure of the grown films was evaluated by scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. The Ta thin film grown by HPPMS has a smooth surface and a dense crystalline structure with grains oriented perpendicular to the substrate surface, whereas the film grown by dcMS exhibits a rough surface, pores between the grains, and an inclined columnar structure. The improved homogeneity achieved by HPPMS is a direct consequence of the high ion fraction of sputtered species.
TL;DR: In this article, the authors used X-ray diffraction and piezoelectric atomic force microscopy to study the evolution of the ferroelectric polarization as the ratio of PbTiO3 to SrTiO 3 was changed.
Abstract: Artificial PbTiO3/SrTiO3 superlattices were constructed using off-axis rf magnetron sputtering. X-ray diffraction and piezoelectric atomic force microscopy were used to study the evolution of the ferroelectric polarization as the ratio of PbTiO3 to SrTiO3 was changed. For PbTiO3 layer thicknesses larger than the 3-unit cell SrTiO3 thickness used in the structure, the polarization is found to be reduced as the PbTiO3 thickness is decreased. This observation confirms the primary role of the depolarization field in the polarization reduction in thin films. For the samples with ratios of PbTiO3 to SrTiO3 of less than one, a surprising recovery of ferroelectricity that cannot be explained by electrostatic considerations was observed.
TL;DR: In this paper, N-doped TiO2 films were deposited on n+-GaN∕Al2O3 substrates by reactive magnetron sputtering and subsequently crystallized by annealing at 550 °C in flowing N2 gas.
Abstract: N-doped TiO2 films were deposited on n+-GaN∕Al2O3 substrates by reactive magnetron sputtering and subsequently crystallized by annealing at 550 °C in flowing N2 gas. The N-doping concentration was ∼8.8%, as determined from x-ray photoelectron spectroscopy measurements. Deep-level optical spectroscopy measurements revealed two characteristic deep levels located at ∼1.18 and ∼2.48eV below the conduction band. The 1.18 eV level is probably attributable to the O vacancy state and can be active as an efficient generation-recombination center. Additionally, the 2.48 eV band is newly introduced by the N doping and contributes to band-gap narrowing by mixing with the O2p valence band.
TL;DR: In this article, nanolayered TiAlN/CrN multilayer films were deposited on silicon substrates from a TiAl target using a reactive DC magnetron sputtering process in Ar+N 2 plasma.
TL;DR: The growth of large-area, patterned and oriented ZnO nanowires on silicon using a low temperature silicon-CMOS compatible process is demonstrated and can be used to integrate patterned 1D nanostructures in optoelectronic and sensing applications on standard silicon CMOS wafers.
Abstract: The growth of large-area, patterned and oriented ZnO nanowires on silicon using a low temperature silicon?CMOS compatible process is demonstrated. Nanowire synthesis takes place using a thin nucleation layer of ZnO deposited by radiofrequency magnetron sputtering, followed by a hydrothermal growth step. No metal catalysts are used in the growth process. The ZnO nanowires have a wurtzite structure, grow along the c-axis direction and are distributed on the silicon substrate according to the pre-patterned nucleation layer. Room temperature PL measurements of the as-grown nanowires exhibit strong yellow?red emission under 325?nm excitation that is replaced by ultraviolet emission after annealing. This method can be used to integrate patterned 1D nanostructures in optoelectronic and sensing applications on standard silicon CMOS wafers.
TL;DR: In this paper, the effect of temperature dependence on response magnitude and the influence of the metal activator layers for hydrogen gas sensitivity are presented and discussed, and the effects of different operating temperatures on the sensitivity of the devices were studied in the range of 30-300 ÂC.
Abstract: The hydrogen gas sensing performance of platinum (Pt) and gold (Au) catalyst activated WO 3 thin films were investigated. The WO 3 thin films were deposited onto alumina transducers with platinum inter-digital electrodes using a R.F. magnetron sputtering. Exposure to hydrogen gas, results in changes in the carrier concentration and hence, the conductivity of the film. The sensors were found to exhibit excellent sensitivities towards different hydrogen concentrations of 0.125, 0.25, 0.50 and 1% in air. The effects of different operating temperatures on the sensitivity of the devices were studied in the range of 30–300 °C. It was observed that the Pt–WO 3 and Au–WO 3 sensors were approximately 161 and 40 times more sensitive than the non-activated WO 3 sensor, respectively. In this paper, the effect of temperature dependence on response magnitude and the influence of the metal activator layers for hydrogen gas sensitivity are presented and discussed.
TL;DR: In this paper, a DC magnetron sputtering system was used to deposit coatings in an Ar+N2 discharge at constant N2 partial pressure and bias voltage onto high-speed steel substrates.
Abstract: Ti1–xAlxN hard coatings are already successfully applied for cutting tool applications with extreme conditions. Special emphasis in this field is laid on high hardness, oxidation resistance and superior tribological properties. The aim of this work is to present a comprehensive study on the influence of the Al content on coating microstructure and related mechanical and tribological properties. A DC magnetron sputtering system was used to deposit coatings in an Ar+N2 discharge at constant N2 partial pressure and bias voltage onto high-speed steel substrates. Ti1–xTAlxT targets with atomic ratios xT=0.5, 0.6, 0.67 and 0.75 were used. By X-ray diffraction and transmission microscopy the fcc single-phase coatings at low Al contents and dual-phase or hcp coatings at higher Al contents are investigated in detail. Hardness measurements showed high values of 33 GPa for x=0.54 in the coating, decreasing with increasing Al to values of 19 GPa at x=0.76. Friction coefficients against stainless steel balls were high at room temperature with values around 1.5, but decreased significantly at higher temperatures to 0.88 at 700 °C. The wear performance was better for dual-phase and hcp coatings with high Al contents compared to fcc coatings. This investigation shows clearly the relations between target and coating composition, where the resulting structure specifies their mechanical and tribological properties.
TL;DR: In this article, high-resolution transmission electron microscopy was used to show that overstoichiometric TiB2 has a complex self-organized columnar nanostructure, which is thermally stable to postannealing temperatures up to 700°C.
Abstract: TiB2 thin films are well known for their high hardness which makes them useful for wear-resistant applications. Overstoichiometric TiB2 deposited at 300 °C by nonreactive sputtering has been shown to exhibit superhardness (H⩾40GPa), while the hardness of their bulk stoichiometric counterparts is ∼25GPa. We show, using high-resolution transmission electron microscopy, that overstoichiometric TiB2.4 layers have a complex self-organized columnar nanostructure. The ∼20nm wide columns, encapsulated in excess B and oriented along 0001, consist of a bundle of ∼5nm diameter TiB2 subcolumns separated by an ultrathin B-rich tissue phase. The nanocolumnar structure, which is thermally stable to postannealing temperatures up to 700 °C, inhibits nucleation and glide of dislocations during hardness indentation measurements, while the high cohesive strength of the B-rich tissue phase prevents grain-boundary sliding. The combination of these effects results in the observed superhardness of ∼60GPa.
TL;DR: In this paper, magnetron sputtering is applied to synthesize MAX-phase films of several systems including Ti-SiC, Ti-GeC, and Ti-Al-N, which can be deposited at 900-1000 °C on Al2O3(0001) and MgO(111) pre-seeded with TiC or Ti(Al)N.
Abstract: We report that magnetron sputtering can be applied to synthesize MAX-phase films of several systems including Ti–Si–C, Ti–Ge–C, Ti–Al–C, and Ti–Al–N. In particular, epitaxial films of the known phases Ti3SiC2, Ti3GeC2, Ti2GeC, Ti3AlC2, Ti2AlC, and Ti2AlN as well as the newly discovered thin film phases Ti4SiC3, Ti4GeC3 and intergrown structures can be deposited at 900–1000 °C on Al2O3(0001) and MgO(111) pre-seeded with TiC or Ti(Al)N. From XTEM and AFM we suggest a growth and nucleation model where MAX-phase nucleation is initiated at surface steps or facets on the seed layer and followed by lateral growth. Differences between the growth behavior of the systems with respect to phase distribution and phase stabilities are discussed. Characterization of mechanical properties for Tin+1Si–Cn films with nanoindentation show decreased hardness from about 25 to 15 GPa upon penetration of the basal planes with characteristic large plastic deformation with pile up dependent on the choice of MAX material. This is explained by cohesive delamination of the basal planes and kink band formation, in agreement with the observations made for bulk material. Measurements of the electrical resistivity for Ti–Si–C and Ti–Al–N films with four-point probe technique show values of 30 and 39 μΩ cm, respectively, comparable to bulk materials.
Patent•
13 Jan 2005TL;DR: In this article, a continuous in situ process of deposition, etching, and deposition is provided for forming a film on a substrate using a plasma process, and the etch-back may be performed without separate plasma activation of the etchant gas.
Abstract: A continuous in situ process of deposition, etching, and deposition is provided for forming a film on a substrate using a plasma process. The etch-back may be performed without separate plasma activation of the etchant gas. The sequence of deposition, etching, and deposition permits features with high aspect ratios to be filled, while the continuity of the process results in improved uniformity.
TL;DR: In this paper, the ion beam mixing and He accumulation in multilayer thin films after 33keV He implantation at room temperature to a dose of 1.5×1017atoms∕cm2 were studied.
Abstract: We studied ion beam mixing and He accumulation in Cu∕Nb multilayer thin films after 33keV He implantation at room temperature to a dose of 1.5×1017atoms∕cm2. Multilayered thin films consisting of alternating Cu and Nb layers were produced by magnetron sputtering. Two types of samples, one with an individual layer thickness of 4nm and another with 40nm were examined. The Cu∕Nb samples were analyzed in the as-deposited state, after He ion implantation, as well as after post-implantation annealing. The ion beam mixing of the interface structure was monitored by Rutherford backscattering spectrometry and cross-section transmission electron microscopy imaging. Elastic recoil detection analysis was performed to examine the helium concentration depth distribution. Scanning electron microscopy was employed to investigate He blister formation upon annealing. A comparison of the results deduced from the methods listed above reveals a very high morphological stability of the nanolayered structure. The nanolayered structure of the Cu∕Nb multilayer thin films is retained. He bubbles were observed to reside within the layers but more so at the Cu∕Nb incoherent interfaces.
TL;DR: In this article, highly sensitive XPS investigations were performed and the chemical and phase compositions of a film surface range of about 10 nm thickness was estimated quantitatively from the deconvoluted peak intensities.
Abstract: Cr–N film coatings were prepared by magnetron sputter deposition at different nitrogen partial pressures. The film characterisation by XRD and DTG gives average bulk compositions of Cr2N and CrN for the coatings. Highly sensitive XPS investigations were performed and the chemical and phase compositions of a film surface range of about 10 nm thickness was estimated quantitatively from the deconvoluted peak intensities. It is demonstrated that the composition of the surface of chromium nitride thin films differs from the core and is more complex in constitution. Not only chromium nitrides (Cr2N and CrN) but also chromium oxynitrides and chromium oxides (CrOx and CrOxHy) were detected. Metallic chromium was also found in films prepared at higher nitrogen flow. The concentration of the estimated phases shows dependence on film preparation and additional heat treatment.
TL;DR: In this article, the crystal structure and the film/electrode interface of BFO films were characterized using x-ray diffraction and scanning transmission electron microscope high-angle annular dark-field imaging.
Abstract: BiFeO3 (BFO) thin films of pure perovskite phase were deposited on LaNiO3-buffered Pt∕TiOx∕SiO2∕Si (LNO) and Pt∕TiOx∕SiO2∕Si (Pt) substrates by RF magnetron sputtering. Highly (100)-oriented BFO film was coherently grown on LNO at a temperature as low as 300 °C. The crystal structure and the film/electrode interface of BFO films were characterized using x-ray diffraction and scanning transmission electron microscope high-angle annular dark-field imaging. The conventional problem of the leakage current was greatly reduced with remarkable improvement in the film/electrode interface, chemical homogeneity, crystallinity, and surface roughness of the BFO film.
TL;DR: In this paper, the resistance switching behavior and switching mechanism of nonstoichiometric zirconium oxide thin films were investigated for nonvolatile memory application, which can be explained by electron trapping and detrapping of excess Zr/sup +/ ions in transition layer which control the distribution of electric field inside the oxide, and hence the current flow.
Abstract: The resistance switching behavior and switching mechanism of nonstoichiometric zirconium oxide thin films were investigated for nonvolatile memory application. The Pt/ZrO/sub x//p/sup +/-Si sandwich structure fabricated by reactive sputtering shows two stable resistance states. By applying proper bias, resistance switching from one to another state can be obtained. The composition in ZrO/sub x/ thin films were confirmed from X-ray photoelectron spectroscope (XPS) analysis, which showed three layers such as top stoichiometric ZrO/sub 2/ layer with high resistance, transition region with medium resistance, and conducting ZrO/sub x/ bulk layer. The resistance switching can be explained by electron trapping and detrapping of excess Zr/sup +/ ions in transition layer which control the distribution of electric field inside the oxide, and, hence the current flow.
TL;DR: In this article, a polycrystalline rutile TiO2 thin film was obtained after annealing at 1000 8C for 1 h. The maximum UV-visible transmittance and hardness of the film were over 90% and 1700 HK 0.025, respectively.