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

Issue 4 • Date Jul 2009

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Displaying Results 1 - 25 of 84
  • Low temperature grown polycrystalline La0.7Sr0.3MnO3 thin films on amorphous SiO2 substrates by rf magnetron sputtering

    Page(s): 595 - 600
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    The La0.7Sr0.3MnO3 thin films have been prepared on amorphous SiO2 substrates by a rf magnetron sputtering technique under various oxygen flow rates and rf powers at a relatively low substrate temperature of 350 °C. The effects of oxygen flow rate and rf power on their physical properties were systematically investigated. X-ray diffraction results show that the growth orientation and crystallinity of the films were affected by rf power and oxygen flow rate. The electrical resistivity of the films was reduced with increasing oxygen flow rate and rf power due to enhanced {100} growth plane orientation and enlarged grain size of the films. In addition, a relatively high temperature coefficient of resistance value of -2.4% was obtained in the present investigation even with low deposition temperature. View full abstract»

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  • Collisionless gas flows over a flat cryogenic pump plate

    Page(s): 601 - 610
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    This article concerns collisionless gas flows over a flat cryogenic pump plate with a specific sticking probability. It presents exact density, velocity, temperature, and pressure solutions which are useful in determining the plate sticking probability. At any point off the plate, the local velocity distribution function (VDF) consists of several pieces of Maxwellian VDFs, one is characterized by free stream flow properties and the others by plate surface properties. Integrating the VDFs with different moments leads to these exact solutions, which are further validated by simulations with the direct simulation Monte Carlo (DSMC) method. We use these solutions to derive several useful expressions, based on special measured flow field properties at specific locations off the plate, to evaluate the pump sticking probability. Also, the exact solutions complement past studies of aerodynamic coefficients and heat transfer rate for collisionless gas flowing over a flat plate. They explicitly express the physical and geometrical factors. Evaluations of those solutions are much faster than DSMC simulations. This study can find other useful applications, e.g., cold gas spray for thin film depositions inside a vacuum chamber, and spacecraft plume impingement estimations. View full abstract»

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  • Surface effects on the luminescence degradation of hydride vapor-phase epitaxy-grown GaN induced by electron-beam irradiation

    Page(s): 611 - 613
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    Luminescence degradation of hydride vapor-phase epitaxy-grown GaN wafers under electron-beam (e-beam) irradiation was studied. A drastic decrease in the band-edge emission is observed under e-beam irradiation. This degradation may be decomposed into two components: a strong and quick decrease in the first minute and a smaller and more gradual decrease. It is found that the vacuum condition also affects the luminescence of GaN since the degradation amplitude becomes smaller when the specimens are kept in ultrahigh vacuum. These results suggest that the adsorbed species at the surface may affect the luminescence properties of GaN. View full abstract»

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  • Fabrication of surface plasmon waveguides on thin CYTOP membranes

    Page(s): 614 - 619
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    The fabrication of a membrane supported long-range surface plasmon polariton waveguide for use as a biosensor is described. This type of device can be completely immersed in the sensing environments to create symmetrical waveguide surroundings. The membrane is created from the fluoropolymer CYTOP which has strong physical properties and a low index of refraction. The fabrication steps of this device are described along with examples of completed structures. View full abstract»

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  • Large crystal grain niobium thin films deposited by energetic condensation in vacuum arc

    Page(s): 620 - 625
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    This article presents evidence for unprecedented, large crystal grain size in ∼1 μm thick Nb films that were grown on sapphire and copper substrates using a vacuum arc process called coaxial energetic deposition CED™. Most other deposition techniques with low adatom energy produce amorphous or small crystal-grain films. Typically, high substrate temperatures and annealing steps are required to form the large, highly connected grains. The CED™ technique deposits from plasma consisting of a nonequilibrium, high energy (50–150 eV) ion population produced from the ionized source material. At the substrate these fast ions break up columnar structures, intermix with the first few atomic layers of the substrate to improve adhesion, and form dense films at lower substrate temperatures than are typical for low adatom energy techniques, such as physical vapor deposition (PVD). Nanoscale features of the thin films were examined using electron backscatter diffraction (EBSD). The films’ cryogenic state electrical properties were characterized by their residual resistivity ratio (RRR) and superconducting transition temperature (Tc). RRR of ∼77 and Tc∼9.2 K were measured on a Nb thin film deposited on a sapphire substrate. EBSD and x-ray diffraction measurements indicated that the sapphire substrate thin films have single crystal structure, with a Nb {110} crystal plane monolithically aligned and parallel to the sample surface. Nb thin films on an ∼400 °C Cu substrate had average crystal grain size of 50 μm, which is an order of magnitude larger than that which is typical of films grown by PVD. The crystal structure of CED™ t- hin films is comparable to that of polycrystalline bulk Nb material, which is the state of the art for superconducting radio frequency (SRF) particle accelerators such as at the Thomas Jefferson National Accelerator Facility (JLab). The films’ novel crystal features suggest that CED™ is a promising technique to coat Nb thin films for lower cost SRF particle accelerators. Further studies of the nanoscale grain boundary features would shed light on the role played by these features in determining the performance of SRF cavities using such thin films on Cu. View full abstract»

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  • Studies on hard TaN thin film deposition by R C-Mag technique

    Page(s): 626 - 630
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    The physical and mechanical properties of pulsed rotating cylindrical magnetron sputter-grown tantalum nitride (TaN) thin films were studied. Initially, films were grown at ambient substrate temperature by varying the reactive (N2) to sputter (Ar) gas ratio (R) at a constant pulsing frequency of the target power (100 kHz). The results were compared with planar magnetron-grown TaN samples. The R C-Mag. grown thin films have properties nearly similar to the high temperature (300 °C) dc planar magnetron sputter deposited samples. In comparison to the planar magnetron deposition, the progression of the phase composition occurs over a wider range of R in the pulsed R C-Mag. deposition. These observed differences for R C-Mag. deposition are attributed to the increased glancing angle deposition of adatoms and pulsing of the target power. To study the effect of pulsing frequency of the target power in R C-Mag., the films were also grown at different frequencies at a fixed R (0.1). With the increase in frequency, the mechanical hardness increased up to 50 kHz and started decreasing beyond 50 kHz. The observed changes in the mechanical hardness are attributed to the increase in stress and to the formation of increased polycrystalline understoichiometric TaN phases. View full abstract»

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  • Relationship between gas-phase chemistries and surface processes in fluorocarbon etch plasmas: A process rate model

    Page(s): 631 - 642
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    In a typical plasma tool, both etch and deposition occur simultaneously. Extensive experimental measurements are used to help develop a general model of etch and deposition processes. This model employs reaction probabilities, or surface averaged cross sections, to link the measurable surface processes, etch and deposition, to the flux of various species to the surfaces. Because the cross sections are quantum mechanical in nature, this surface rate model should be applicable to many low temperature plasma processing systems. Further, the parameters that might be important in reaction cross sections are known from quantum mechanics, e.g., species, energy, temperature, and impact angle. Such parameters might vary from system to system, causing the wide processing variability observed in plasma tools. Finally the model is used to compare measurements of ion flux, ion energy, and fluorocarbon radical flux to the measured process rates. It is found that the model appears to be consistent with calculations of gain/loss rates for the various radicals present in the discharge as well as measured etch and deposition rates. View full abstract»

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  • Effect of cesium assistance on the electrical and structural properties of indium tin oxide films grown by magnetron sputtering

    Page(s): 643 - 647
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    Indium tin oxide (ITO) thin films were deposited by cesium (Cs)-assisted dc magnetron sputtering in an attempt to achieve a high performance at low temperatures. The films were deposited on SiO2/Si wafer and glass (Eagle 2000) substrates at a substrate temperature of 100 °C with a Cs vapor flow during the deposition process. The ITO thin films deposited in the presence of Cs vapor showed better crystallinity than the control films grown under normal Ar/O2 plasma conditions. The resistivity of the films with the Cs assistance was lower than that of the control films. The lowest resistivity of 6.2×10-4 Ω cm, which is ∼20% lower than that of the control sample, was obtained without any postdeposition thermal annealing. The surface roughness increased slightly when Cs vapor was added. The optical transmittance was ≫80% at wavelengths ranging from 380 to 700 nm. View full abstract»

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  • Thermal stability of sputter deposited nanomosaic rutile TiO2

    Page(s): 648 - 652
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    A domain structure based on the rutile lattice with a large density of 12<011>{011}-type stacking faults is found in sputter deposited TiO2 films [J. Vac. Sci. Technol. A 24, 2054 (2006)]. The thermal stability of nanomosaic rutile at moderate temperature is reported here. Films are annealed at 973 K for 0.25–15 h, characterized by x-ray diffraction. A Johnson–Mehl–Avrami–Kolmogorov analysis indicates impeded crystallite growth. A dislocation-locking mechanism is proposed for this behavior. Partial dislocations with 12<011> Burgers vectors that bound the stacking faults glide on intersecting {011} slip planes and react to produce sessile stair rod dislocations. Without the high temperature required for dislocation climb, 12<011>{011}-type faults inherent to nanomosaic rutile provide thermal stability against massive crystallite growth. View full abstract»

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  • Rotation magnet sputtering: Damage-free novel magnetron sputtering using rotating helical magnet with very high target utilization

    Page(s): 653 - 659
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    Novel magnetron-sputtering equipment, called rotation magnet sputtering (ROT-MS), was developed to overcome various disadvantages of current magnetron-sputtering equipment. Disadvantages include (1) very low target utilization of less than 20%, (2) difficulty in obtaining uniform deposition on the substrate, and (3) charge-up damages and ion-bombardment-induced damages resulting from very high electron temperature (≫3 eV) and that the substrate is set at the plasma excitation region. In ROT-MS, a number of moving high-density plasma loops are excited on the target surface by rotating helical magnets, resulting in very high target utilization with uniform target erosion and uniform deposition on the substrate. This excellent performance can be principally maintained even if equipment size increases for very large-substrate deposition. Because strong horizontal magnetic fields (≫0.05 T) are produced within a very limited region just at the target surface, very low electron-temperature plasmas (≪2.5 eV for Ar plasma and ≪1 eV for direct-current-excited Xe plasma) are excited at the very limited region adjacent to the target surface with a combination of grounded plate closely mounted on the strong magnetic field region. Consequently, the authors can establish charge-up damage-free and ion-bombardment-induced damage-free processes. ROT-MS has been applied for thin-film formation of LaB6, which is well known as a stable, low-work-function bulk-crystal material for electron emissions. The work function of the LaB6 film decreased to 2.8 eV due to enhanced (100)-orientation crystallinity and reduced resistivity realize- d by adjusting the flux of low-energy bombarding ions impinging on the depositing surface, which work very efficiently, improving the performance of the electron emission devices. View full abstract»

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  • Characterization of ALD copper thin films on palladium seed layers

    Page(s): 660 - 667
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    A method for fabricating monolithic nanoscopic tunnel junctions (MNTJs) for tunneling spectroscopy measurements using atomic layer deposition (ALD) of Cu on Pd seed layers has recently been introduced [Gupta and Willis, Appl. Phys. Lett. 90, 253102 (2007)]. The ALD grown layers are characterized here using planar thin films as models for the nanoelectrode composition and structure. ALD Cu films grown on Pd seed layers using a varying number of deposition cycles were characterized using transmission electron microscopy, Auger electron spectroscopy (AES), and glancing incidence x-ray diffraction (GIXRD) to investigate the chemical composition and structure of the nanoelectrodes. Electron diffraction and GIXRD show that as Cu is deposited, the bulk composition progresses from being Pd rich to becoming predominately Cu. In contrast, AES data show that significant Pd consistently remains on the surface of the growing film. The divergence in surface and bulk behaviors is attributed to Pd surface segregation that is driven by hydrogen adsorption during the ALD process. In contrast to the results for Pd seed layers, it is demonstrated that Pt seed layers can be used to grow pure Cu ALD films. This is because hydrogen adsorption does not induce Pt surface segregation within the ALD temperature window. View full abstract»

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  • Particle-induced x-ray emission in stainless steel using 30 keV Ga+ focused ion beams

    Page(s): 668 - 671
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    Characteristic x-ray emission from a well grounded stainless steel specimen using standard 30 keV Ga+ focused ion beam instrumentation is demonstrated. X-ray yields are found to be on the order of 10-10 per incident ion, consistent with previous studies of low energy, high mass ion-solid interactions. X-ray yields were found to be highest for low energy transitions or low atomic number target atoms. Bremsstrahlung x-ray emission was found to be minimal, possibly increasing detectability compared with electron beam induced x-rays. Yields were also estimated to be on the order of 10-11 per sputtered atom, or approximately one x-ray per sputtered monolayer. While velocity coupling between the primary ion beam and target atom electrons is not possible under these experimental conditions, it is argued that x-ray emission is, in fact, due to recoil effects of the ion-solid interaction. View full abstract»

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  • Structure and mechanical properties of nanoscale multilayered CrN/ZrSiN coatings

    Page(s): 672 - 680
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    Nanocrystalline/amorphous CrN/ZrSiN multilayer coatings with a bilayer thickness ranging from 11 to 153 nm were prepared by reactive magnetron sputtering technique. The microstructure and mechanical properties of these thin films were characterized by x-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and nanoindentation. The formation of nanocrystalline CrN and nanocomposite ZiSiN in the single layer coatings was identified by XRD and FTIR. The periodic structure of the as-deposited multilayer coatings was confirmed by TEM observation. Nanoindentation tests showed that both the values of hardness (H) and reduced elastic modulus (Er) of CrN/ZrSiN multilayers remained almost constant despite varying the bilayer thickness. The multilayer coatings exhibited higher H of 30 GPa and higher resistance to plastic deformation when compared to the single layer CrN and ZrSiN coatings. View full abstract»

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  • Inductively coupled plasma-reactive ion etching of InSb using CH4/H2/Ar plasma

    Page(s): 681 - 685
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    InSb is an important material for optoelectronic devices. Most InSb devices are currently wet etched, and the etching geometries are limited due to the isotropic nature of wet etching. Inductively coupled plasma (ICP)–reactive ion etching (RIE) is a more desirable alternative because it offers a means of producing small anisotropic structures especially needed in large format infrared focal plane arrays. This work describes the novel use of ICP-RIE for fabricating InSb mesas with CH4/H2/Ar plasma and presents the influences of the process parameters on the etch rate and surface morphology. The parameters investigated include bias radio frequency power (50–250 W), % CH4 in H2 (10–50), argon (Ar) partial pressure (0–0.3 Pa with total pressure of 1.0 Pa), and total pressure (0.35–4 Pa). With the process parameters optimized in this investigated ranges, good etching results have been achieved with etch rates up to 80 nm/min, and etch features with sidewall angles of about 80°, the etched surface is as smooth as before the RIE process. View full abstract»

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  • Establishment of very uniform gas-flow pattern in the process chamber for microwave-excited high-density plasma by ceramic shower plate

    Page(s): 686 - 695
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    The authors developed a ceramic upper shower plate used in the microwave-excited high-density plasma process equipment incorporating a dual shower-plate structure to establish a very uniform gas-flow pattern in the process chamber. Thousands of very fine gas-injection holes are implemented on this Al2O3 upper shower plate with optimized allocation to establish a uniform gas-flow pattern of plasma-excitation gases and radical-generation gases for generating intended radicals in the plasma-excitation region. The size of these fine holes must be 50 μm or less in diameter and 8 mm or more in length because these holes perform an essential role: They completely avoid the plasma excitation in these fine holes and upper gas-supply regions resulting from the plasma penetration into these regions from excited high-density plasma, even if very high-density plasma greater than 1×1012 cm-3 is excited just under the ceramic upper shower plate by microwaves supplied from the radial line slot antenna. On the other hand, various process gases, such as material gases for film formations and etching gases, are supplied from the lower shower plate installed in the diffusion plasma region to this very uniform gas-flow pattern region of plasma-excitation gases and radical-generation gases. As a result, the process gases are supplied to the wafer surface in a very effective manner without excess decomposition of those process gas molecules and undesired reaction-product deposition on the inner surface of the process chamber. The process results are improved drastically by introducing the newly developed ceramic upper shower plate. But also, process uniformity on the entire wafer is improved with drastically reducing reaction-product deposition on the inner sur- face of the process chamber. View full abstract»

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  • Low-temperature growth of InN on Si(100) by femtosecond pulsed laser deposition

    Page(s): 696 - 699
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    InN films were grown on Si(100) using femtosecond pulsed laser deposition. Laser induced breakdown of ammonia was used to generate atomic nitrogen for InN growth. An indium buffer layer was initially deposited on the Si substrate at low temperature followed by an InN intermediate layer. The crystal quality and surface morphology were investigated by reflection high-energy electron diffraction during growth and atomic force microscopy and x-ray diffraction after growth. The results showed that the In(2×1) initial buffer layer improved the quality of the InN film. High quality InN films were grown at a temperature of ∼350 °C. View full abstract»

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  • Silicon-oxide-high-κ-oxide-silicon memory using a high-κ Y2O3 nanocrystal film for flash memory application

    Page(s): 700 - 705
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    In this article, the authors developed a silicon-oxide-high-κ-oxide-silicon (SOHOS) memory structure using a high-κ Y2O3 nanocrystal film as the charge-trapping layer for flash memory applications. From x-ray photoelectron spectroscopic and atomic-force microscopy analyses, they found that the Y2O3 nanocrystal layer formed after O2 and N2O annealing. When using the channel hot-electron injection for charging and the band-to-band hot hole for discharging, the high-κ Y2O3 SOHOS memory devices prepared under the N2O gas annealing exhibited large threshold-voltage shifting (memory window of ∼3 V), superior endurance characteristics (program/erase cycles of up to 105), and excellent data retention (charge loss of ∼7.5% measured time up to 104 s and at room temperature). These results indicate the higher probability of charge-carrier trapping in the Y2O3 film. View full abstract»

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  • Effects of interelectrode gap on high frequency and very high frequency capacitively coupled plasmas

    Page(s): 706 - 711
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    Capacitively coupled plasma (CCP) discharges using high frequency (HF) and very high frequency (VHF) sources are widely used for dielectric etching in the semiconductor industry. A two-dimensional fluid plasma model is used to investigate the effects of interelectrode gap on plasma spatial characteristics of both HF and VHF CCPs. The plasma model includes the full set of Maxwell’s equations in their potential formulation. The peak in plasma density is close to the electrode edge at 13.5 MHz for a small interelectrode gap. This is due to electric field enhancement at the electrode edge. As the gap is increased, the plasma produced at the electrode edge diffuses to the chamber center and the plasma becomes more uniform. At 180 MHz, where electromagnetic standing wave effects are strong, the plasma density peaks at the chamber center at large interelectrode gap. As the interelectrode gap is decreased, the electron density increases near the electrode edge due to inductive heating and electrostatic electron heating, which makes the plasma more uniform in the interelectrode region. View full abstract»

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  • Nitrogen stabilized reactive sputtering of optimized TiO2-x photocatalysts with visible light reactivity

    Page(s): 712 - 715
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    Photoreactive and visible light responsive nonstoichiometric mixed-phase titania was prepared by reactive direct current magnetron sputtering. Trace amounts of nitrogen were added for process stabilization without being incorporated into the films. Based on the CO2 photoreduction tests and structural and optical characterization, the influence of the trace nitrogen on the sputtered nonstoichiometric TiO2 was studied and was compared to nitrogen-doped titania. View full abstract»

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  • Nucleation and growth of tantalum nitride atomic layer deposition on Al2O3 using TBTDET and hydrogen radicals

    Page(s): 716 - 724
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    The nucleation and growth of tantalum nitride atomic layer deposition (ALD) was investigated on Al2O3 ALD surfaces on silicon substrates using tertbutylimino trisdiethylamino tantalum (TBTDET) and hydrogen radicals as the reactants. The hydrogen radicals were generated using a hot tungsten filament. Auger electron spectroscopy (AES) was utilized to monitor the atomic composition of the surface versus the TBTDET/hydrogen radical reaction cycles. These studies were conducted in a vacuum apparatus with a sample introduction port, two ALD reactors, and a connecting surface analysis chamber. Initial results with the silicon substrates at 250 °C revealed tantalum nitride ALD growth and the oscillation of the N AES signal during the TBTDET/hydrogen radical reaction cycles. However, TBTDET pyrolysis was a problem on the BN heater. The TBTDET pyrolysis threshold of ∼250 °C on the BN heater limited the maximum substrate temperature to 170 °C. The AES results revealed that the composition of the tantalum nitride ALD films grown at 170 °C was TaNx where x∼1. In addition, there were carbon and oxygen impurities in the TaNx film. Aluminum and tantalum AES signals were employed to determine the tantalum nitride ALD thickness on the underlying Al2O3 ALD surface during TBTDET/hydrogen radical reaction cycles at 170 °C. The Cumpson method of using the ratio of the Al and Ta AES signals to determine the TaNx<- /formula> ALD film thickness avoided the problem of normalization between different AES spectra. The TaNx ALD nucleated readily on the Al2O3 ALD surface. The Al AES signal approached zero after 20 reaction cycles. The corresponding tantalum nitride film thickness was determined to be 11.6 Å after 20 reaction cycles. The film thickness at 5, 10, 15, and 20 reaction cycles yielded an initial ALD growth rate of 0.5 Å/cycle. The ALD growth rate increased to 0.7 Å/cycle for ≫10 reaction cycles. The efficient initial nucleation and reasonable growth rates for tantalum nitride ALD are desirable for the formation of copper diffusion barriers on interconnection vias. View full abstract»

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  • Physical and optical properties of room temperature microwave plasma anodically grown TiO2

    Page(s): 725 - 730
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    A dense, amorphous form of TiO2 produced by plasma assisted anodic oxidation of Ti was identified using infrared absorption, x-ray diffraction, x-ray reflectivity, atomic force microscopy, and ellipsometry. The films were grown by nominally room temperature processing. Comparison of the physical properties of the material is made with respect to existing data on plasma enhanced chemical vapor deposited TiO2 and new data obtained on electron beam evaporated TiO2. Anodic TiO2 is found to be amorphous with a refractive index of the order of 2.33 as compared to 2.2 for plasma enhanced chemical vapor deposited films and 1.89 for electron beam evaporated TiO2 films. The density is measured to be 4.1 g/cm3. Samples annealed up to 600 °C in a N2 atmosphere for 1 h remained amorphous, the refractive index increasing to 2.38 and the density to 4.25 g/cm3. The surface roughness remained almost unchanged consistent with the amorphicity. No evidence for the presence of crystalline rutile or anatase phases was detected. Furthermore, unlike plasma assisted chemical vapor deposited and electron beam evaporated TiO2 films, annealed anodic TiO2 showed no observable interaction with the Si substrate either during growth or following annealing. View full abstract»

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  • Ge nanocrystals embedded in a GeOx matrix formed by thermally annealing of Ge oxide films

    Page(s): 731 - 733
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    The authors investigate the formation of Ge nanocrystals by thermal annealing of substoichiometric GeOx films fabricated by electron-beam evaporation. At the same time, they also monitor the evolution of the GeOx matrix. The phase separation into semiconductor and oxide phases and the evolution of Ge nanocrystals were monitored by a combination of x-ray diffraction (XRD), Raman, and transmission electron microscopy (TEM) measurements. TEM shows spherical particles of sizes in the range of 2–9 nm. They infer that an annealing temperature of 500 °C is sufficient to generate a reasonable density of Ge nanocrystals in an amorphous GeOx matrix. Both XRD and Raman measurements suggest a simultaneous crystallization of the matrix at an annealing temperature of 600 °C. View full abstract»

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  • Preface

    Page(s): 736
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    First Page of the Article
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  • Scanning Auger of a specific via interface in an integrated circuit using a novel focused ion beam sample preparation technique

    Page(s): 738 - 742
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    Auger depth profile analysis can be impeded by surface roughening during ion sputtering. This is especially noticeable when analyzing semiconductor devices because of the variety of materials that are susceptible to roughening, as well as the importance of very thin interfaces. A novel technique is presented in this article, which combines scanning Auger analysis with focused ion beam (FIB) thinning for analysis of single via interfacial structures in integrated circuit devices. After a failing structure was identified by electrical fault isolation techniques, FIB was used to remove all of the materials from the top of the device. The materials include polyimide, passivation, metal layers, and dielectric layers. The layers were removed to a level approximately 100 Å above the via interface under a tungsten plug. A scanning Auger instrument was then used for Auger depth profiling of the single via. A thin oxidized interface was observed between Ti/TiN glue layer and antireflection coating (ARC) TiN and was identified as the cause of the via failure. It would have been impossible for conventional sputter depth profiling to detect this thin oxidized layer buried under several layers of materials. Further investigation showed that the interfacial oxide is caused by backsputtering of ARC TiN during via etch and rf sputtering before Ti/TiN glue deposition. View full abstract»

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  • X-ray photoelectron spectroscopy analysis of organic materials etched by charged water droplet impact

    Page(s): 743 - 747
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    Electrospray droplet impact (EDI) has been developed for matrix-free secondary ion mass spectrometry for surface analysis. When a target is etched by EDI, the physical etching on the target is suppressed to minimal, i.e., the occurrence of shallow surface etching. A novel approach to shallow surface etching of polystyrene (PS) by EDI was investigated. The charged water droplets were irradiated to a bulk and a spin coated PS. After irradiation, these samples were analyzed by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy. It was found that XPS spectra for PS were independent on the irradiation time by EDI. This indicates that EDI is a unique technique for the surface etching of the organic materials without leaving any damage on the etched surface. View full abstract»

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Aims & Scope

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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Editor
G. Lucovsky
North Carolina State University