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Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures

Issue 2 • Date Mar 2002

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Displaying Results 1 - 25 of 46
  • Issue Cover

    Page(s): c1
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    Freely Available from IEEE
  • Issue Table of Contents

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    Freely Available from IEEE
  • Nucleation and film growth during copper chemical vapor deposition using the precursor Cu(TMVS)(hfac)

    Page(s): 495 - 506
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    This article describes a study of chemical vapor deposition (CVD) copper thin films deposited on TaNx substrates using Cu(TMVS)(hfac) as a precursor. We have characterized the deposition rate, resistivity, surface roughness, and reflectivity of the films as functions of substrate temperature, precursor and carrier gas flow rates, and the presence or absence of water vapor as a coreactant. We have also examined the nucleation process for these films as functions of substrate temperature and the presence or absence of water vapor. We observed an activation energy for nucleation of 39 kcal/mol and an activation energy for film growth of 14 kcal/mol. Introducing water vapor during nucleation reduces the activation energy for nucleation to 6.1 kcal/mol. We found that water vapor helps to reduce the incubation time and activation energy of the nucleation stage and enhances nuclei formation, uniformity, and adhesion. In our reactor, the highest quality films were obtained using a process protocol for Cu CVD in which small amounts of water vapor were introduced before or during the initial stage of deposition at 473 K substrate temperature. © 2002 American Vacuum Society. View full abstract»

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  • Comparison of secondary ion mass spectroscopy analysis of ultrashallow phosphorus using Cs+, O2+, and CsC6- primary ion beams

    Page(s): 507 - 511
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    It is well known that reducing the work function of the sample surface using Cs+ ions increases the negative ion yield of phosphorus. It is also well known that a shallow primary beam implantation depth (RP) is required for achieving high depth resolution during the analysis of ultrashallow implant profiles. The combination of the opposite polarities of the positive Cs+ primary ion beam and the negatively biased sample (the combination most often used for P analysis using magnetic sector secondary ion mass spectroscopy) unfortunately accelerates the Cs+ ions towards the sample thus limiting the degree to which the primary ion impact energy can be reduced [R. Loesing, G. M. Guryanov, J. L. Hunter, and D. P. Griffis, J. Vac. Sci. Technol. B 18, 509 (2000)]. A low primary ion beam impact energy and high impact angle, both of which result in lower RP, can be obtained using a negatively charged cluster ion such as CsC6- (Peabody negative ion source) impacting on a negatively biased sample [G. Gillen, L. King, B. Freibaum, R. Lareau, and J. Bennett, in Secondary Ion Mass Spectrometry, SIMS XII, edited by A. Benninghoven etal (Elsevier, Amsterdam, 2000), p. 279; R. Loesing, G. M. Guryanov, and D. P. Griffis, in Proceedings of the 13th Annual SIMS Workshop, Lake Tahoe, 2000, p. 36]. If, however, Cs is not required to improve secondary ion yield, a low energy O2+ primary beam impacting on a positively biased sample can be used [I. M. Abdelrehim, T. H. Büyüklimanli, S. P. Smith, and C. W. Magee, in Secondary Ion Mass Spectrometry SIMS XII, edited by A. Benninghoven (Elsevier, Amsterdam, 2000), p. 279; S. P. Smith, C. J. Hitzman, and C. W. Magee, in Secondary Ion - - Mass Spectrometry, SIMS XI, edited by G. Gillen (Wiley, Chichester, 1998), p. 277]. In this case, the reduction in sensitivity for P due to the loss of the negative ion yield enhancing Cs can be partly compensated by flooding the sample surface with oxygen. In this study Cs+, CsC6-, and O2+ primary ions are compared for depth profiling of ultrashallow phosphorus in Si in terms of decay length, sensitivity, and crater bottom roughness. © 2002 American Vacuum Society. View full abstract»

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  • Band offsets of AlxGa1-xSbAs/InGaAs heterojunctions

    Page(s): 512 - 522
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    By applying van de Walle and Martin’s model solid theory (MST), we have investigated the compositional dependence of the band-edge alignment at the AlxGa1-xSbAs/InGaAs and AlxGa1-xSbAs/InAlAs heterointerfaces lattice-matched to InP. A comparison between theoretical calculations and previously published experimental values on ternary extremes of AlxGa1-xSbAs yields a discrepancy of 0.1–0.2 eV for GaSbAs/InAlAs and GaSbAs/InGaAs, and 0.3 eV for AlSbAs/InAlAs and AlSbAs/InGaAs. For all four heterostructures, it has been found that the MST results shift the valence band edge of the (Sb, As) alloy downward relative to that of InAlAs and InGaAs as compared to experimental data, and possible causes of the disagreement are analyzed. Furthermore, the band offset values have been obtained from a current–voltage measurement on InGaAs/AlxGa1-xSbAs/InGaAs semiconductor–insulator–semiconductor diodes. The carrier transport mechanism in these diodes is discussed and the measured offset values are shown to be in qualitative agreement with the MST predictions. © 2002 American Vacuum Society. View full abstract»

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  • Coalescence inhibition in nanosized titania films and related effects on chemoresistive properties towards ethanol

    Page(s): 523 - 530
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    Achievement of nanosized thin films of titania was achieved by radio-frequency sputtering of a Ti(97%)–Mo(3%) target. Deposition was performed under inert or reactive atmosphere followed by annealing at temperatures up to 800 °C. The resulting layers became more stoichiometric as annealing temperature increased. The small part of Mo proved useful to prevent exaggerated grain coalescence. Reactive sputtering was more effective than inert deposition to achieve a nanograined layer with lowest size (31 nm). Mo segregated at the surface and partially sublimated as MoO3. The layers became n-doped semiconductors and were tested as chemoresistive gas sensors. Good capability to sense ethanol was determined within a range useful for applications. A model was proposed to explain the response to ethanol. © 2002 American Vacuum Society. View full abstract»

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  • Recent advances in resists for 157 nm microlithography

    Page(s): 531 - 536
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    The synthesis and characterization of several new fluoropolymers designed for use in the formulation of photoresists for exposure at 157 nm will be described. The design of these platforms has in some cases been inspired by ab initio quantum mechanical calculations of excited state transition energies and by interpretation of gas phase VUV spectrophotometric data. We have explored anionic polymerizations, free radical polymerizations, metal-catalyzed addition polymerizations and metal-catalyzed copolymerizations with carbon monoxide in these studies. The polymers and resist formulations were characterized by VUV spectrometry and variable angle spectroscopic ellipsometry (VASE). Resist formulations based on these polymers were exposed at the 157 nm wavelength to produce high-resolution images that will be presented. © 2002 American Vacuum Society. View full abstract»

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  • Advancements to the critical ionization dissolution model

    Page(s): 537 - 543
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    The microlithographic process is dependent upon the dissolution of acidic polymers in aqueous base. The fundamental mechanism that governs the dissolution of these polymers has been the subject of considerable discussion, and a number of theories have been proposed to explain this behavior. Our research group has presented the critical ionization (CI) dissolution model to explain the dissolution of phenolic polymers in aqueous base. Specifically, the model proposes that a minimum or critical fraction of ionized sites, fcrit, on a given polymer chain must be ionized in order for that chain to dissolve. The main input parameters to this model are the critical fraction of ionized sites, fcrit, and the fraction of ionized surface sites, α. In this work methods are established for measuring these parameters. A quantitative link between the CI model and experiment has been demonstrated for the dissolution rate and surface roughness dependence on polymer molecular weight. Methods for calculating α are discussed, including a new method that considers the formation of an electrostatic double layer at the resist–developer interface. © 2002 American Vacuum Society. View full abstract»

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  • Influence of the cap layer on the Gibbs free energy above a layer of buried InGaAs islands

    Page(s): 544 - 547
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    The Gibbs free energy above a layer of buried InxGa1-xAs islands embedded in a GaAs cap layer is calculated as a function of the cap thickness and mole fraction of the dots. The model is based on a three-dimensional calculation of the elastic strain within the continuum elastic theory. A surface map of the Gibbs free energy due to strain variations is a useful guide in understanding the vertical ordering of dots as well as cooperative nucleation in the lateral direction. The calculated results have implications for determining how thick a cap layer can be before preferential nucleation above a layer of buried stressors ceases. Additionally, the Gibbs potential depth is estimated for varying In composition of the buried pyramidal stressors. It is found that even a slight change in the shape of the island can influence the degree of screening that the GaAs cap exerts on the Gibbs potential. © 2002 American Vacuum Society. View full abstract»

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  • Investigation of temperature coefficient of resistance and crystallization of semiconducting YBaCuO thin films using pulsed laser annealing

    Page(s): 548 - 553
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    We explored the electrical and dielectric properties of yttrium barium copper oxide (YBa2Cu3O6+x) with different oxygen content. The aim was to perform a study of the annealing conditions using a pulsed laser annealing (PLA) system to obtain optimum temperature coefficient of resistance (TCR) for bolometric structures and low loss tangent for pyroelectric structures without causing a thermal damage to the underlying layers. Oxygen content of samples was changed by annealing with an excimer laser (λ=248 nm) at different power levels and pulse number under high vacuum. X-ray diffraction patterns of these samples were taken to examine the level of crystallization. We observed different crystallization levels for different annealed samples. For bolometric samples, semiconducting YBaCuO thin films were deposited by rf sputtering at room temperature on oxidized Si wafers. The films were amorphous to polycrystalline as deposited. PLA was performed on the samples at varying number of pulses from 100 to 300 at two power levels of 20 and 25 mJ/cm2. The purpose was to decrease the oxygen content of the samples, thus making them more resistive with higher TCR, while simultaneously increasing the long range atomic order and hence crystallinity. For dielectric properties, the samples were fabricated following the model of a capacitor. 2000 Å YBaCuO was sandwiched between two 3000 Å Nb electrodes with an effective area 7.35×10-4 cm2 in contact with the substrate. The annealing was done with 50 pulses at power levels of 25 and 40 mJ/cm2. Our aim was to achieve a small loss tangent through PLA, thus decreasing the amount of power dissipated in the capacit- - or for pyroelectric detection applications. Capacitance and resistance measurements were done at different temperatures to calculate the loss tangent. © 2002 American Vacuum Society. View full abstract»

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  • Chemically dependent traps and polytypes at Pt/Ti contacts to 4H and 6H–SiC

    Page(s): 554 - 560
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    We have used low energy electron-excited nanoluminescence (LEEN) spectroscopy and x-ray photoemission spectroscopy (XPS) to probe deep level defect states at interfaces of 4H and 6H–SiC with Ti/Pt metallization. These studies aim to identify process conditions under which thermally stable ohmic and Schottky contacts can be obtained on SiC while minimizing the formation of deep level electronic states. Depth-dependent LEEN measurements establish the presence of localized states and their spatial distribution on a nanometer scale. Spectra from the near interface region of 6H–SiC indicate the existence of a SiC polytype with a higher band gap of ∼3.4 eV. Excitation of the intimate metal–SiC interface reveals a process-dependent discrete state deep within the SiC band gap. XPS measurements reveal consistent differences in the C 1s chemical bonding changes with specific process steps. Analogous chemical treatments of 4H–SiC also produce a lower band gap SiC polytype with ∼2.5 eV energy extending tens of nanometers beyond the interface—confirmed by transmission electron microscopy. This work is the first to show the effect of metal–semiconductor interactions not only on localized states but also on the lattice structure of the semiconductor near the interface. © 2002 American Vacuum Society. View full abstract»

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  • Gap-filling capability and adhesion strength of the electroless-plated copper for submicron interconnect metallization

    Page(s): 561 - 565
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    The major goal of this study is to combine the plasma immersion ion implantation (PIII) to implant Pd catalyst onto a TaN diffusion barrier layer and the electroless plated Cu to accomplish the ultralarge scale integrated interconnection metallization. Both patterned and nonpatterned wafers were employed using Pd as a catalyst by PIII after which copper was electroless plated onto a TaN/FSG/Si multilayer structure. The Pd atoms were sputtered from a negatively biased target and ionized in an argon inductively coupled plasma. The Pd ions were adequately implanted into the substrate with a highly pulsed negative bias (∼4000 V). Characterized by field enhanced scanning electron microscopic (FESEM) cross-section images of FESEM, and under the circumstances of higher substrate bias voltage and plasma ionization, the electroless copper grows upward from the bottom of the vias (width: 0.25 μm, aspect ratio: 7), with an excellent gap filling ability. The result of this process, by employing the mechanical pull-up tests, showed that higher substrate bias and higher plasma ionization can effectively enhance the adhesion strength between the copper film and the TaN layer. © 2002 American Vacuum Society. View full abstract»

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  • Photocapacitance of deep levels in GaP crystals surface treated by reactive ion etching

    Page(s): 566 - 569
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    Damaged layers of GaP crystals surface treated by reactive ion etching using PCl3 gas are evaluated by capacitance–voltage, secondary ion mass spectroscopy, and photocapacitance (PHCAP) measurements. The reduction of the carrier concentration is observed at the surface region within the depth of 60–70 nm, where Cl atoms injected with high energy are observed. PHCAP measurement reveals that density of the deep levels increases with decreasing gas pressure. The deep levels are thought to be the complexes of shallow donor impurities and intrinsic point defects. © 2002 American Vacuum Society. View full abstract»

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  • Use of reflective and amorphous materials for dark field stepper alignment on silicon carbide substrates

    Page(s): 570 - 574
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    A method of performing fine alignment for stepper lithography using a dark field alignment system (DFAS) has been developed for low reflectivity substrates. This patented process is useful for substrates such as silicon carbide (SiC), which do not provide adequate reflected light in DFAS systems for alignment mark detection. The method involves forming alignment mark structures from thin films of materials that have the following two characteristics: adequate reflectance to broadband illumination typical of DFAS systems and a fine-grained or amorphous morphology. Alignment mark materials must also be resistant to grain growth during high temperature (950 °C) anneals common to SiC processing to avoid any increase in surface roughness which can lower mark contrast. This study includes modeling of the reflectivity of several candidate materials and characterization of film surfaces using atomic force microscopy. © 2002 American Vacuum Society. View full abstract»

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  • pH-mediated frictional forces at tungsten surfaces in aqueous environments

    Page(s): 575 - 579
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    We have used atomic-force microscopy to measure the change in interfacial friction and adhesion between a tungsten surface and bare or alumina-coated Si3N4 tips. These measurements have been made in aqueous solutions ranging in pH from 2.2 to 8.2 in the absence of chemical or mechanical dissolution of the surface oxide. Friction is observed to vary with solution pH, and the specific manner in which interfacial friction depends on pH is influenced by the composition of the interface. The maximum friction force of the tungsten/silicon nitride system occurs at a pH of 4.7. The tungsten/alumina system has a maximum in the frictional force at a pH of 6.6. Frictional variations in these systems are related to pH-mediated changes in the electrostatic interaction between the probe tip and the sample. The pH dependence of the electrostatic interaction is determined by the relative isoelectric points of the contacting surfaces. These nanometer-scale measurements demonstrate a fundamental pathway by which variations in the frictional properties of an interface are introduced by properties of the surrounding liquid environment. © 2002 American Vacuum Society. View full abstract»

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  • Epitaxially overgrown, stable W–GaAs Schottky contacts with sizes down to 50 nm

    Page(s): 580 - 589
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    A processing scheme for the fabrication of embedded W–GaAs contacts has been established and the resulting contact characteristics have been evaluated. The main advantage of these contacts is that they are stable during high-temperature epitaxial overgrowth. The fabrication scheme is based on a liftoff process with electron beam evaporation of tungsten and subsequent epitaxial overgrowth using metalorganic vapor phase epitaxy. Various methods were used to characterize the buried contacts. First, the structural properties of GaAs surrounding embedded W features, with widths down to 50 nm, were characterized by high-resolution transmission electron microscopy. Measurements of the conductivity in individual, buried wires were performed in order to study the influence of the overgrowth process on the properties of the tungsten. We also evaluated the current–voltage characteristics for macroscopic contacts, which revealed a clear dependence on processing parameters. Optimized processing conditions could thus be established under which limited contact degradation occurred during overgrowth. Finally, we used the overgrowth technique to perform a detailed investigation of the electrical and optical properties of floating-potential embedded nano-Schottky contacts by space-charge spectroscopy. © 2002 American Vacuum Society. View full abstract»

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  • Characterization of platinum films deposited by focused ion beam-assisted chemical vapor deposition

    Page(s): 590 - 595
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    This work presents results from the characterization of ion-assisted chemical vapor deposition of platinum from trimethyl–methylcyclopentadienyl–platinum (C9H16Pt). Films were deposited in squares ranging from 50 to 200 μm on a side using a focused ion beam system. The effects of Ga+ ion flux and precursor flux on the deposited films’ composition and resistivity were determined. Films were characterized using atomic force microscopy, Rutherford backscattering spectrometry, and Auger electron spectroscopy. Results show that increasing precursor flux at constant ion flux increases Pt and C, but decreases Ga content of the film. Increasing ion flux at constant precursor flux increases Pt content, while decreasing C content of the films. Resistivity did not depend on the thickness of 50–200 nm thick films. Resistivity was shown to follow C content, with films with lower C content having lower resistivity. © 2002 American Vacuum Society. View full abstract»

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  • High-resolution in situ electron beam patterning using Ti(OC3H7)4 as a negative-type resist

    Page(s): 596 - 603
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    Our previous studies on the electron beam resist properties of inorganic titanium isopropoxide films condensed on semiconductor surfaces addressed mainly the electron sensitivity of this negative-type resist, i.e., the contrast curve behavior. In order to determine its resolution capabilities, we have used scanning electron microscopy to analyze the pixel sizes and shapes that result after exposing condensed titanium isopropoxide films of various thicknesses (from as low as the 10’s of Å range to as high as 10 000 Å) to a scanning electron beam for different times. We have found that resolution is strongly dependent on initial film thickness and electron beam exposure. While occurring at the lowest electron exposure, the smallest, well-defined pixels were observed with films on the order of 100 Å; thinner films (in the 10’s of Å range) resulted in pixels with poor definition. For films with sufficient thickness, dual pixel behavior was observed above a critical electron exposure, in which a narrow pixel with height approximating the initial film thickness would appear at the center of a thin, a broader area pixel that was observed for all exposures. Moreover, the broad area pixel’s height was relatively insensitive to initial thickness and exposure. By qualitative comparison with standard electron-resist scattering models in the literature, we argue that the thin, a broad area pixel is an artifact of the backscattered electron component generated from the interaction of the electron beam with the substrate, whereas the narrow and thick central pixel that appears after sufficiently high exposures, is representative of the forward-scattered electron distribution of the incident beam within the resist film. © 2002 American Vacuum Society. View full abstract»

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  • Study of the SiO2/Si interface using spectroscopic ellipsometry and x-ray reflectometry

    Page(s): 604 - 607
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    To analyze the structure of the SiO2/Si interface, we developed a method that uses spectroscopic ellipsometry and x-ray reflectometry simultaneously. We applied this method to the characterization of SiO2 grown in dry oxygen. We found that the thickness of the interface layer showed no significant dependence on the oxidation temperature and oxide film thickness. The mean value of the interface layer density was 2.31 g/cm3, clearly higher than that of the upper layer, which was 2.28 g/cm3. Furthermore, we found that the distribution of the interface layer density in the 6 in. wafer was similar to the distribution of the interface state density, Dit, which was obtained by the charge-pumping method using metal–oxide–semiconductor field-effect transistors with SiO2 formed in the same oxidation process. This fact strongly suggests that the density of the interface layer is correlated closely with the electrical characteristics of the SiO2/Si interface. © 2002 American Vacuum Society. View full abstract»

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  • Electrochemical behavior of copper chemical mechanical polishing in KIO3 slurry

    Page(s): 608 - 612
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    The electrochemical behavior of polishing copper with colloidal silica abrasive slurry formulated with KIO3 oxidizer has been investigated. For planarization of the surface morphology, the control of the surface passivation of Cu is critical during polishing. KIO3 is not only an oxidizer but also a passivator for copper in an acidic slurry by forming a CuI layer on the surface. With alkaline slurry, Cu2O is the primary corrosion product on the Cu surface. The copper corrosion rate and removal rate can be decreased dramatically with increasing slurry pH. The low corrosion resistance or high corrosion susceptibility of Cu as determined by electrochemical measurements is the basis for the high removal rates. The copper removal rate is reduced from 4600 to 650 Å/min when the slurry pH is increased from 2 to 5; and the copper removal rate levels off at pH 7 with a steady-state removal rate of 200 Å/min. © 2002 American Vacuum Society. View full abstract»

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  • Optimum B+ implantation conditions for the edge termination of the Au/n-Si Schottky diodes

    Page(s): 613 - 617
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    Boron ion implantation for edge termination was performed as a simple technique to improve the breakdown characteristics in Au/n-Si Schottky diodes. Four doses of 1×1013, 1×1014, 1×1015, and 1×1016Bcm-2 were implanted at the ion energy of 30 keV. The Schottky diode implanted with the dose of 1×1013Bcm-2 shows the best edge termination characteristics. In addition, 20, 40, and 50 keV ion energies were also adopted to investigate the influences of implantation energies on edge termination in the Schottky diodes. The current–voltage measurement results show that the diode implanted with 1×1013Bcm-2 at 30 keV has the highest breakdown voltage of 386 V while the diode treated at 20 keV has the abrupt breakdown at only 150 V. Leakage currents at the reverse bias are attributed to the deep level defects introduced by ion implantation. Using two-dimensional simulation, it is verified that the anomalous breakdown phenomena in the diode implanted at 20 keV result from the high electric field near the Au contact edge. © 2002 American Vacuum Society. View full abstract»

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  • Nanofabrication of photonic crystal membrane lasers

    Page(s): 618 - 621
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    We present techniques for fabricating photonic crystal (PC) membrane defect lasers. These nanostructures operate as optically pumped lasers under pulsed conditions at room temperature. The thin membrane PC defect structures are formed by transferring an electron-beam lithographically defined lattice pattern into an epitaxial layer structure by a sequential process of ion beam etching, reactive ion etching, and electron cyclotron resonance etching steps. A V-shape undercut channel is formed by a wet chemical etching using a 4:1 mixture of HCl and H2O to create the suspended membrane. We include a detailed description of a dependable and repeatable HCl undercut process for the PC structure. © 2002 American Vacuum Society. View full abstract»

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  • Atomistic simulations of deep submicron interconnect metallization

    Page(s): 622 - 630
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    Damascene approaches are widely used for creating microelectronic interconnects. Successful implementation of the process is reliant upon the deposition of a refractory metal or metal nitride liner coating. It functions as a diffusion barrier layer to suppress transport of subsequently deposited interconnect metals into the surrounding dielectric. The development of vapor-phase processes for the deposition of uniform thickness liner layers has been problematic. Flux collimation and energetic deposition approaches have been attempted with mixed results as the feature size is decreased. Here, a modified kinetic Monte Carlo (KMC) method has been used to explore the physical vapor deposition of liner coatings. To incorporate the many effects associated with energetic metal fluxes, the results of molecular dynamics calculations of incident atom reflection, resputtering, surface biased diffusion, and athermal relaxations have been introduced into the KMC algorithm. The method has been applied to investigate the effects of the incidence flux’s angular distribution and kinetic energy upon the liner coating coverage. It has been found that trench step coverage uniformity increases with increasing atom kinetic energy above a threshold energy value of 20 eV. Atom resputtering/reflection are found to be the most important mechanisms responsible for improvements in the step coverage. Sputtering of already deposited material is found to be the most important mechanism for transporting the flux to the most difficult to coat lower sidewall region of a trench. Energetic deposition processes that activate these mechanisms are therefore preferred. The simulations reveal the existence of an optimal incident angular distribution to maximize coverage uniformity. For a flux with a kinetic energy of 70 eV, a cosine angular distribution within the collimation angle of ±15°–25° provided the best balance of direct and resputtered/reflected fluxes to maximize - - coating uniformity. © 2002 American Vacuum Society. View full abstract»

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  • Ge-rich Si1-xGex nanocrystal formation by the oxidation of an as-deposited thin amorphous Si0.7Ge0.3 layer

    Page(s): 631 - 634
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    Ge-rich Si1-xGex nanocrystals are formed by the selective oxidation of Si during the dry oxidation processing of an amorphous Si0.7Ge0.3 layer. The oxidation kinetics of the alloy film in the temperature ranges from 600 to 800 °C are well explained by the classical model proposed by Deal and Grove with the activation energies of the linear rate and parabolic rate regime of about 1.35 and 1.02 eV, respectively. As a result of the selective oxidation process, Ge-rich Si1-xGex nanocrystals are formed with the size of 5.6±1.7 nm and with the spatial density of 3.6×1011/cm2 at 600 °C. With an increase of the oxidation temperature to 700 and 800 °C, the size of the nanocrystal is increased to about 20 nm. The variation of size of the nanocrystals as a function of temperature is explained considering the solid phase crystallization of amorphous film, oxidation rate, and grain growth. © 2002 American Vacuum Society. View full abstract»

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  • Effect of de-ionized water parameters rinse on postmetal etch residue removal using semiaqueous cleaning chemistries

    Page(s): 635 - 639
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    As the plasma etch processes have evolved, the wet cleaning process has included resist stripping, sidewall polymer removal, and also encompasses surface cleaning, which can include mobile ion reduction and damaged metal removal. This scenario has ushered in the recent popularity of fluoride based semiaqueous cleaning (SAC) chemistries for postmetal etch cleaning. These chemicals can include low or room temperature operation and very short process times, are easily rinseable in water, and are easy to dispose of. This study looks at the effects of cleaning metal and via structures with SAC chemistries. The primary focus is on metal integrity when looking at: (1) process latitude of the cleaning chemicals; (2) the effect of de-ionized water rinsing; and (3) the effect of utilizing different intermediate rinses. This study shows that an emphasis should now be placed on total process optimization. This not only includes the cleaning chemistry, but also the rinsing process, which had historically not been a focus item. © 2002 American Vacuum Society. View full abstract»

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Aims & Scope

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

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Editor
Gary E. McGuire
International Technology Center