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Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films

Issue 3 • Date May 1990

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Displaying Results 1 - 25 of 325
  • Issue Table of Contents

    Page(s): toc1
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    Freely Available from IEEE
  • Ion‐assisting magnetron sources: Principles and uses

    Page(s): 1277 - 1282
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    The design and performance of magnetron sources which provide at the substrate not only the flux of sputtered atoms but also fluxes of electrons and ions from the plasma are described. This energetic particle bombardment (which is directed to the substrate by an unbalanced magnetic field design) can be beneficial, as when it is used to ion assist the growth of the depositing thin film, or deleterious, e.g., by providing extra heating. Applications of unbalanced magnetrons to investigate the technology of magnetron sputtering are described. Ion assistance of the growing film increases the biaxial compressive stress in the growing film due to an atomic peening process. The lattice strain produced by the stress can be measured using x‐ray diffraction, and can be used to quantify the degree of ion assistance. Effects studied in films of refractory metals include the increase in stress until plastic flow occurs during growth, changes in preferential orientation, the effectiveness of the different gases Ar and Xe in producing stress, energetic neutral bombardment, and moderation of sputtered atoms. New results are presented here for the temperature dependence of the stress production in molybdenum films. The application of unbalanced magnetrons to industrial deposition processes is discussed. View full abstract»

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  • Role of nitrogen ions in ion‐beam reactive sputtering of NbN

    Page(s): 1283 - 1287
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    Using ion‐beam reactive sputtering of a niobium target, we have studied the effects of energetic‐nitrogen‐ion bombardment on the target reaction and on the resulting NbN film properties. Nitrogen is either added into the ion source with the noble gas to obtain a beam of nitrogen and argon ions, or injected directly into the chamber as neutral molecules so the ion beam is composed of essentially all argon. The target reaction rate is seen to be controlled by the adsorbed thermal nitrogen, and only minimally affected by the presence of ionized nitrogen. Thus, argon‐ion bombardment of the target is responsible for stimulating the reaction between the adsorbed nitrogen and the metal target producing the NbN layer. However, the film properties are affected by the presence of nitrogen ions. Films grown with N2 added in the ion source have a higher resistivity and lower superconducting transition temperature than films grown with N2 injected directly into the chamber. These differences increase with N2 flow; the differences are attributed to damage of the growing film by energetic nitrogen reflecting from the target, as measured by an energetic‐neutral‐particle detector. View full abstract»

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  • Properties of reactively sputtered NbN films

    Page(s): 1288 - 1293
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    The variation of the properties of niobium nitride (NbN) thin films as a function of argon partial pressure and nitrogen flow were studied. The films were deposited by dc reactive planar magnetron sputtering onto unheated substrates. All of the films were superconducting and had the B1, face‐centered cubic crystal structure. A number of films deposited at argon partial pressures of 5 and 7 mTorr had superconducting critical temperatures (Tc ) of 15.6 K and grain sizes of 100–120 nm. The film morphology showed a zone 1 to zone T transition as the argon partial pressure was decreased from 12 to 5 mTorr. Films deposited below 5 mTorr exhibited excessive tensile stress (≫1.9×109 N/m2) and delaminated from the substrate. View full abstract»

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  • A comparison of SiO2 planarization layers by hollow cathode enhanced direct current reactive magnetron sputtering and radio frequency magnetron sputtering

    Page(s): 1294 - 1298
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    SiO2 films have been prepared by hollow cathode enhanced dc reactive magnetron sputtering [J. J. Cuomo and S. M. Rossnagel, J. Vac. Sci. Technol. A 4, 393 (1986)], and for comparison by rf magnetron sputtering from an SiO2 target. The hollow cathode arc source is used in a triode configuration with the magnetron. This configuration allows sputtering to take place at pressures as low as 5×10-4 Torr, as well as sputtering of the oxide without arcing below ∼600 V. These films were investigated as a dielectric planarization layer for Josephson (superconducting) devices. To this end, film deposition parameters (O2 flow rate, Ar partial pressure, magnetron target voltage, hollow cathode current) have been related to film deposition rate, index of refraction, measured by ellipsometry, stoichiometry, measured by x‐ray photoelectron spectroscopy (XPS), and coating conformity as measured by electron microscopy. A similar set of experiments was performed for the rf sputtered films. The relationships were investigated using factorial experiment design. View full abstract»

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  • Film thickness distribution control with off‐axis circular magnetron sources onto rotating substrate holders: Comparison of computer simulation with practical results

    Page(s): 1299 - 1303
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    Film thickness distribution control in magnetron sputtering systems is of vital importance to the researcher or process engineer, especially when performing cosputtering of superconducting and alloy films. It is time consuming to find the relative spatial position of sources, substrates, and rotational geometry by experiment to obtain optimum film uniformity. A mathematical computer model for film uniformity is developed to enable rapid prediction of optimum geometries using target erosion data. Aluminum films are deposited by rf magnetron sputtering from 100 and 75 mm diam sources at 5×10-3 mbar in argon onto flat rotating workholders at various source to substrate distances and with varying source offsets from the axis of rotation of the workholder. Film thickness distribution is measured by Talystep. Target erosion profile is measured and this information is used in the computer simulation developed to predict film thickness uniformity. Practical results and theory are in good agreement, demonstrating the usefulness of the computer model. The significance of this technique is that much experimental time can be saved to find the best geometry for optimum film thickness distribution. View full abstract»

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  • Effect of deposition parameters on properties of films deposited on fibers by hollow cathode magnetron sputtering

    Page(s): 1304 - 1312
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    Thin films of Al and TiN were deposited on SiC monofilaments using a hollow cathode magnetron sputtering system. The deposition rate was 1100 Å/min in the case of Al films deposited at 45.75 W direct current power and 5 mTorr sputtering pressure and 257 Å/min for TiN films deposited at 6 mTorr sputtering pressure, 6% N2, and 48 W applied direct current power. The effects of deposition parameters such as the direct current power, sputtering pressure, and substrate bias on the film microstructure were studied. The substrate temperature varied from 67.7 to 168 °C, which corresponds to a T/Tm value of 0.1 to 0.25. The Al films consisted of a voided columnar structure with domed tops. The width of the grains increased with increase in temperature over a T/Tm range of 0.1–0.22. When the pressure was increased, while keeping the power constant, the size of the columnar grains and voids decreased. The TiN films deposited at 6 mTorr exhibited zone 1 type structure with voids whereas for the films deposited at higher pressures, that is, 10 and 15 mTorr, the same effect of pressure as in the case of Al films was seen. When a bias is applied to the substrate, the voided structure is clearly suppressed. Preliminary studies show that bias sputtered films show better diffusion barrier properties against both Si and Al, after being annealed at 650 °C for 6 h, as compared to the films deposited without bias. View full abstract»

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  • Microstructural variations in aluminum oxide coatings deposited using a dual beam ion system

    Page(s): 1313 - 1317
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    We have sputter‐deposited aluminum oxide coatings using a dual ion beam system with a mixture of argon plus 10% oxygen as the working gas. Ambient substrate temperatures and substrate temperatures of 360 °C were maintained. The coatings were deposited at deposition rates between 7 and 10 nm/min, with and without concurrent ion bombardment from the second ion gun. Substantial variations in the microstructure and the amount of entrained gas in the coatings were observed. The coatings contain a mixture of varying amounts of γ‐Al2O3 and amorphous aluminum oxide. Relatively large, 0.5 μm islands of γ‐Al2O3 crystallites surrounded by an amorphous matrix were observed in coatings deposited onto heated substrates with ion bombardment from the second ion gun during deposition. Coatings bombarded with a second ion beam during deposition contain more argon as determined by energy dispersive x‐ray analysis. The Raman spectra exhibited by the coatings suggest a variation in chemical reactivity and/or porosity which depends on the deposition conditions. View full abstract»

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  • Sputtering systems with magnetically enhanced ionization for ion plating of TiN films

    Page(s): 1318 - 1324
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    The reactive sputtering of hard coatings as TiN in large distances and/or on large substrates is difficult to perform with the conventional magnetron. A strong magnetic confinement of plasma between the magnetron target and substrates enhances the gas ionization and raises the ion current Is extracted to substrates. A new sputtering system with a multipolar magnetic plasma confinement (MMPC) is described. It consists of a planar unbalanced magnetron (UM), with diameter 120 mm equipped with two magnetic coils, and coupled to a closed multipolar magnetic field formed by a set of permanent magnets located on the internal surfaces of the deposition chamber. Typical operation characteristics of the new sputtering system are presented. It can be operated in a wide range of pressure from 5 to 0.02 Pa. The influence of different magnetic field configurations on Is and on the floating potential Ufl of substrates is also reported and compared with the characteristics of the UM without the multipolar field. Operation characteristics favorable for ion plating are observed. Ion current densities is on substrates exceed 2 mA/cm2 even at negative bias Us below 60 V and on substrates placed in large distances as 200 mm from the target. The floating potential Ufl of substrates ranges from -5 to -50 V. Under these conditions are deposited dense golden TiN films with stresses as low as 2 to 3 GPa. View full abstract»

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  • Beam parameter effects on magnetic properties of sputtered amorphous Fe40Ni40B15Si5 and Fe40Co40B15Si5 films

    Page(s): 1325 - 1329
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    Amorphous films were deposited onto fused quartz by ion beam sputter deposition to examine possible alternatives to existing polycrystalline microwave materials. Ion beam parameters were systematically varied to determine the dependence of film magnetic properties on beam conditions. Chemical composition of representative films were confirmed using Auger electron spectroscopy and Rutherford backscattering spectroscopy. Amorphousness was confirmed by x‐ray diffraction analysis, and film thickness was determined by surface profilometer trace. Film magnetic properties were measured by vibrating sample magnetometer and ferromagnetic resonance techniques. It was found that films deposited under higher beam energies showed the lowest coercivities and anisotropy fields. Saturation magnetization values remained largely unaffected by beam parameter variation. Evidence suggests vacuum base pressure plays a significant role in film magnetic properties. Improvement of the films’ soft magnetic properties with increased beam energy may be attributed to reductions in trapped impurities resulting from increased deposition rates. The resulting films display promising properties for microwave magnetic applications. View full abstract»

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  • Process parameter‐growth environment‐film property relationships for the sputter deposited yttrium–oxygen system

    Page(s): 1330 - 1334
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    In this study, a Y target was sputtered in radio frequency (rf)‐excited, rare gas discharges (Ne, Ar) containing 0%–40% O2, operated at cathode voltage from -1.0 to -1.7 kV. In situ optical emission spectrometry was used to monitor two neutral excited Y atom transitions (λ=0.6191, 0.6793 μm) and an excited O atom transition (λ=0.7774 μm) as a function of changing process parameter. Films were grown on fused SiO2 substrates, and their crystallography, optical behavior, and electrical resistivity was determined. A ‘‘phase diagram’’ for Y–O not grown under conditions of equilibrium thermodynamics was constructed, and included hexagonal Y, cubic Y2O3, and Y and Y2O3 that had no long range crystallographic order. Two direct optical transitions across the energy band gap of cubic Y2O3, at 5.07 and 5.73 eV, were identified. Combining discharge diagnostics, growth rate, and film property results, it was concluded that Y2O3 was formed at the substrate concurrent with the complete oxidation of the target surface. Even after target oxidation, the discharge contained atomic Y. On the basis of fundamental optical absorption edge characteristics, cubic Y2O3 that more closely resembled the bulk material was obtained when the Y‐oxide molecule/Y atom flux to the substrate was high. View full abstract»

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  • Characterization of sputter‐deposited ZrBxOy films

    Page(s): 1335 - 1339
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    ZrBxOy films for optical durable coating application were deposited by reactive dc magnetron sputtering of Zr–B alloy target on soda‐lime‐silica glass substrate without intentional heating. Effect of boron content on film properties was investigated. The refractive index of the film was decreased from 2.1 to 1.69 corresponding to the increase of B2O3 content from 0 to 64 mol %. The films containing more than 13 mol % B2O3 fraction were amorphous and showed remarkably improved mechanical durability compared with ZrO2 film. More than 51 mol % B2O3 content resulted in degrading of chemical durability. Measurement of mechanical properties was carried out together with characterization on crystalline structure and chemical binding state. View full abstract»

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  • Mechanical properties of high deposition rate SiO2 films

    Page(s): 1340 - 1343
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    Thick overcoats of SiO2 sputtered at high deposition rates in a radio‐frequency (rf) diode system are being considered as alternatives to Al2O3 and photoresist as passivation and planarization layers in the fabrication of thin film magnetic recording heads. The mechanical properties of 7‐μm thick SiO2 films sputtered onto silicon substrates were examined as functions of bias voltage and O2 gas flow. A high rate of 3.69 μm/h was achieved in a production system at substrate temperatures below 40 °C. The addition of O2 decreased the deposition rate to 1.65 μm/h. The decrease in deposition rate produced an improvement in the p‐etch rate, hardness and stress, but no change in the film density or morphology. The addition of a bias voltage during deposition was found to have the biggest effect on film properties. Bias sputtered films were found to be completely devoid of the columnar structure found in films deposited without bias. The addition of a small bias voltage reduced the film stress from -16×108 dyn/cm2 to -0.4×108 dyn/cm2. However, increasing the bias voltage further caused the film stress to increase to -3.6×108 dyn/cm2 at -160 V bias. This effect can be correlated with the increased Ar content of the films. The p‐etch rates of bias sputtered films dropped two orders of magnitude to 10 Å/s. The Knoop hardness increased from 423 without bias to 663 with bias and the film density increased slightly. View full abstract»

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  • Density dependence of the electrochemical characteristics of carbon overcoated thin film media

    Page(s): 1344 - 1347
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    The effectiveness of carbon overcoats as a corrosion barrier for thin film media has been studied. The sputtering pressure and power used during the deposition of the carbon overcoat has a direct influence on its density, and thus upon its corrosion protection characteristics for the underlying metal media. Corrosion rates of the carbon overcoated metal media were measured both electrochemically and by exposing disks to conditions of elevated temperature and humidity. Corrosion measurements show that the corrosion rate of the magnetic media, (sputtered at a constant pressure and power), increases with increased deposition pressure (1–30 mTorr) and decreased sputtering power (2.8–0.3 kW) of the carbon film. The increased corrosion rate is caused by a decrease in density of the carbon film. In another experiment, sputtering pressure was varied in both the magnetic and overcoat layers. Corrosion measurements reveal a relatively small change in corrosion rate for sputtering pressure in the range of 1 to 6 mTorr of Ar, but a significant increase at 30 mTorr. This sharp increase was attributed to an increase in surface area of the magnetic layer believed to be generated by the the formation of rough porous films at high pressure. In this study carbon and magnetic films sputtered at high power and low pressure yield media with the lowest corrosion rate. View full abstract»

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  • A unified integrated model for sputter coating uniformity

    Page(s): 1348 - 1350
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    The net sputter coating flux at the surface being coated can be conceptually divided into two constituent fluxes: the directed flux, and the diffusional flux. The former is due to the high initial velocities of the sputtered target atoms, which tend to move in their original direction even after several collisions with the background gas atoms. The latter exists because of the eventual slowing down of the target atoms to the velocities of equilibrium distribution. At a given sputtering pressure, the directed flux dominates in the vicinity of the target, whereas the diffusional flux dominates away from the target. Coating uniformity on nonplanar substrates depends on the relative contributions from these two fluxes. These two contributions have been extensively modeled in the literature. However, to use the models for any specific situation, one needs to make an a priori assumption about the dominant contribution. In many situations, both these mechanisms are equally significant. It is then difficult to decide which model to apply. We have developed a simplified model that takes into account the gradual transition between the two mechanisms, and thus covers the entire range of relative flux distributions. A decay parameter calculated from experimental data is used to determine the relative contributions from the fluxes. Therefore, with this model, one need not resort to arbitrary assumptions about the controlling contributions, and thus the coating uniformity. We will present the development of the model, computation of the decay parameter, and experimental data that support the model. View full abstract»

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  • The state of residual stress in TiN films made by physical vapor deposition methods; the state of the art

    Page(s): 1351 - 1358
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    Existing transmission electron microscope studies indicate that a variety of lattice defects such as dislocation loops, ultramicrocracking, and trapped argon and its precipitation can be present in thin TiN films, where the precise defects observed in a given sample depend on the deposition conditions of the film. There are also changes in texture and grain size as the film thickness increases. A considerable amount of data has also been reported on the lattice parameters, diffraction peak widths (which indicate the strain distribution), and x‐ray diffraction (XRD) residual stress, which are all found to depend strongly on the deposition conditions of TiN films. These properties also change through the thickness of the film. In the present work, existing XRD data and their trends are reviewed. While it is clear that correlations exist between the XRD data and microscopic and microstructural changes, it is not yet possible to relate them to specific microstructural features or lattice defects. The state of residual stress and the strain distribution are different on different planes in a given film. They also appear to be affected by texture and by the nature of the substrate in a way that cannot yet be classified. View full abstract»

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  • Properties of W–N and Mo–N films prepared by reactive sputtering

    Page(s): 1359 - 1363
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    The structure and properties of W–N films up to 22 μm thick prepared by a reactive dc magnetron sputtering process are reported. It has been found that the properties of the deposited films not only depend on the nitrogen partial pressure in the argon–nitrogen gas mixtures but also on total gas pressure and input power during sputtering. The rate of deposition decreased with increase of nitrogen partial pressure, but was higher at higher total pressure and input power. The resistivity increased with nitrogen partial pressure but was lower at lower total gas pressure and higher input power. The hardness of W–N films could be varied from 600 to 3000 kg/mm2 depending on sputtering conditions. The hardness, in general, increased with nitrogen partial pressure with higher value at higher total pressure and input power. X‐ray diffraction did not indicate presence of nitride phases when the content of nitrogen in the argon–nitrogen gas mixtures during sputtering was below 10%, and the total gas pressure was ≪40 mTorr. W2N was observed when the nitrogen content was over 30% and also when the nitrogen content was over 10% and total gas pressure was over 40 mTorr. These results are consistent with composition determined by the microprobe measurements. Similar studies on Mo–N films made by dc and rf magnetron reactive sputtering methods are reported. Hardness values for the Mo–N films of more than 2200 kg/mm2 have been observed. View full abstract»

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  • Surface hydrogen release during the growth of a‐Si:H by reactive magnetron sputtering

    Page(s): 1364 - 1368
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    We present a study of the hydrogen release step during growth of hydrogenated amorphous silicon (a‐Si:H) thin films. Hydrogen release must occur whenever the hydrogen fraction in the growth flux exceeds the hydrogen incorporation rate into the film, which is usually the case in a‐Si:H deposition. The films in our study are deposited by direct current magnetron sputtering of silicon in an argon–hydrogen atmosphere. In our experiment we monitor the rate of HD production with a mass spectrometer when a deuterated amorphous silicon sample is exposed to a silicon–hydrogen growth flux. Using mass balance arguments, these data, along with known bulk film hydrogen incorporation rates, allow a determination of a lower bound for the rate of reactive hydrogen impingement on the growing surface. Depending on the hydrogen partial pressure in the discharge, we find that about one reacted hydrogen per incorporated silicon arrives at the substrate for typical deposition conditions. In addition, our modeling predicts that the surface of the growing film contains approximately one monolayer of hydrogen. The variation of the reacted hydrogen flux with hydrogen partial pressure and substrate temperature are discussed. View full abstract»

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  • Electronic stability of the reactively sputtered hydrogenated amorphous silicon thin films: The effect of hydrogen content

    Page(s): 1369 - 1373
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    The total hydrogen content (CH) of reactively sputtered hydrogenated amorphous silicon (a‐Si:H) films can be independently controlled by adjusting the partial pressure of hydrogen (PH2) during deposition. We report on the electronic stability of direct‐current (dc) magnetron reactive sputtered films deposited at a constant substrate temperature of 230 °C with various PH2. The films have CH from ∼13 to 28 at. % and similar, device quality properties in the as‐deposited state. The photoconductivities of all the films are between 0.9 to 3×10-5 (Ω cm)-1 under AM‐1 (air mass‐1)illumination (100 mW/cm2). The density of deep states (DOS) measured by the constant photocurrent method is ∼6×1015 cm-3 for low CH (≤15 at. %) and ∼2×1015 cm-3 for high CH (≥17) films. Light induced degradation measurements show a systematic correlation between CH and the electronic stability; the low CH films have a slower rate of photoconductivity decrease, and slower DOS increase, than either the high CH films or one glow‐discharge deposited film tested for comparison. In fact the low CH a‐Si:H appears superior after just a few hours of light exposure. View full abstract»

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  • Local bonding environments of Si–OH groups in SiO2 deposited by remote plasma‐enhanced chemical vapor deposition and incorporated by postdeposition exposure to water vapor

    Page(s): 1374 - 1381
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    We have deposited thin films of SiO2 by remote plasma‐enhanced chemical vapor deposition and have identified similar infrared (IR) spectroscopic signatures of Si–OH groups incorporated during either film growth, or the cooling down process in the deposition chamber. These films can also be hygroscopic and, on postdeposition exposure to atmospheric water vapor, they show changes in the IR spectra associated with the incorporation of additional Si–OH groups. These changes are (i) the development of a new symmetric feature, centered at about 3350 cm-1, within the asymmetric O–H stretching band generated during growth and/or cooling down; (ii) the development of a new spectral feature at 925 cm-1; and (iii) a shift in the Si–O bond‐stretching band to higher wavenumber. We show that the first two changes in the IR spectra are due to near‐neighbor Si–OH bonding groups that result from the reaction between water vapor and the Si–O–Si bonds of the SiO2 host network. These spatially correlated Si–OH groups have different spectral features, due to relatively strong hydrogen bonding interactions, from the randomly distributed Si–OH groups that are incorporated initially during film growth and/or cooling down. The shift in the frequency of the Si–O stretching band derives from a preferential reaction of water with strained and highly reactive Si–O–Si bonding groups, i.e., those with the smallest Si–O–Si bond angles which are attacked by water vapor, resulting in the formation of near–neighbor pairs of Si–OH bonding groups. View full abstract»

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  • Growth and properties of piezoelectric and ferroelectric films

    Page(s): 1382 - 1390
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    Thin films of piezoelectric and ferroelectric materials are playing a growing role as critical elements in microwave acoustic devices, infrared imagers, integrated optic circuits, optical displays, and high‐performance semiconductor memories. In this review, we discuss recent progress in the control of growth, structure, and properties of the main candidate materials, such as ZnO, AlN, PZT‐based solid solutions, bismuth titanate (Bi4Ti3O12), LiNbO3, LiTaO3, and KNO3. Brief mention is also made of the role and status of ferroelectric polymers and liquid crystals. The emphasis of the review is primarily on vacuum‐processed films, intended for integration into solid‐state or semiconductor components. View full abstract»

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  • The effects of biasing and annealing on the optical properties of radio‐frequency sputtered VO2

    Page(s): 1391 - 1394
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    Vanadium dioxide thin films were deposited by radio‐frequency (rf) reactive sputtering. An in situ anneal was found to improve stoichiometry, alter optical contrast, and increase grain size for a set of films. Biasing of a second set of substrates during deposition was found to increase the infrared (IR) transmission of films in the metallic state and degrade hysteresis characteristics. View full abstract»

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  • Low temperature deposition of VO2 thin films

    Page(s): 1395 - 1398
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    VO2 thin films have been deposited by a variety of techniques such as thermal oxidation, reactive evaporation, and magnetron or ion beam sputtering. These methods routinely require deposition temperatures in excess of 400 °C in order to promote crystallization of the VO2 phase. We report on a technique, employing low energy ion bombardment of reactively evaporated VO2, which promotes crystallization of the VO2 phase at temperatures as low as 300 °C. Properties of films deposited at these unusually low substrate temperatures will be discussed. View full abstract»

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  • Low resistivity indium–tin oxide transparent conductive films. I. Effect of introducing H2O gas or H2 gas during direct current magnetron sputtering

    Page(s): 1399 - 1402
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    When an inline sputtering system is used to make conductive transparent ITO film by the direct current (dc) magnetron sputtering method, it was found that the partial gas pressure of H2O affected the properties of deposited films. When the substrate temperature is at or below 200 °C, the control of H2O partial gas pressure is especially important. Using room temperature substrates, an addition of 2×10-5 Torr of H2O in the sputtering process could form ITO films with good repeatability at a low resistivity of 6.0×10-4 Ω cm. By adding H2O gas, it was possible to solve the issue of increased resistivity in thicker films. The films with added H2O gas have H element immersed into the film and have high carrier concentration. Film transmittance stayed constant with or without H2O gas addition. Similar effect was observed by adding H2 gas instead of H2O gas. View full abstract»

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  • Low resistivity indium–tin oxide transparent conductive films. II. Effect of sputtering voltage on electrical property of films

    Page(s): 1403 - 1406
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    A low resistivity and high transmittance Sn doped In2O3 (ITO) film was formed on a glass substrate by dc magnetron sputtering and lower sputtering voltage gave a lower resistivity film. At a sputtering voltage of -250 V, the resistivity obtained was 5.0×10-4Ω cm for room temperature substrate, 2.0×10-4Ω cm for 160 °C substrate, 1.9×10-4Ω cm for 200 °C substrate, and 1.2×10-4Ω cm for 460 °C substrate. At a sputtering voltage of -80 V, the resistivity was 1.3×10-4Ω cm for 200 °C substrate. A measurement of Hall effect shows that the decreased resistivity by lower sputtering voltage is not caused by the Hall mobility but by an increased carrier concentration. View full abstract»

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The Journal of Vacuum Science and Technology A is devoted to reports of original research, review articles, and Critical Review articles.

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G. Lucovsky
North Carolina State University