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

Issue 2 • Date Mar 1995

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Displaying Results 1 - 25 of 53
  • Thermal and electron‐stimulated chemistry of Fomblin–Zdol lubricant on a magnetic disk

    Page(s): 163 - 168
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    The thermal and electron‐induced decomposition of Fomblin–Zdol lubricant on a rigid magnetic disk with a hard carbon overcoat are studied by temperature‐programmed reaction/desorption spectroscopy and electron stimulated desorption. The thermal spectroscopy shows two desorption features peaked at 640 and 700 K resulting from decomposition of the Fomblin–Zdol molecules. The threshold temperature for dissociation of the Fomblin–Zdol molecule is at 500–550 K in accordance with the known thermal stability of the free molecule. HF originating from thermal reactions with either surface OH or surface CH groups is a prominent desorption product. Electron impact also causes Fomblin–Zdol dissociation. Two efficient mechanisms for electron impact dissociation have been resolved separately above and below the ionization threshold of ∼14 eV. The low‐energy process is likely due to the formation of negative ions followed by dissociation (dissociative electron attachment) and has a cross section of ∼2×10-16 cm2. These results show that Fomblin–Zdol as a lubricant on a magnetic disk is inherently unstable thermally and in the presence of triboelectrons. © 1995 American Vacuum Society View full abstract»

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  • Field desorption of lithium fluoride

    Page(s): 169 - 177
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    Layers of lithium fluoride (LiF), ∼10 nm thick, were field desorbed from iridium substrates at temperatures between 25 and 600 °C. The electric field was increased until desorption of the salt layer occurred. Combined mass spectroscopy and field desorption microscopy characterized the desorption process. During desorption, ions of the form (LiF)n∙Li+, n=1–4 are created. The field strength required for desorption is higher at lower temperatures and decreases as the temperature of the substrate is increased. Evidence for a piecewise removal of the LiF layer is presented. For thick salt layers, Li+ ions are frequently detected. An ion production mechanism based on ionic conduction of a salt layer in a high electric field is presented. © 1995 American Vacuum Society View full abstract»

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  • Thermal reactions of fluorocarbon and hydrofluorocarbon species on Si(100)‐(2×1)–CF3I, CF3CH2I, and C2F4

    Page(s): 178 - 182
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    The thermal reactions of CF3I, CF3CH2I, and C2F4 are studied by temperature‐programmed reaction/desorption (TPR/D) on a Si(100) surface. CF3I, CF3CH2I dissociate on the surface, whereas C2F4 adsorbs reversibly, without dissociation. Dissociation of the iodine‐containing molecules is probably initiated by the cleavage of the relatively weak C–I bonds. In the case of CF3I, the C–I bond dissociation generates I(a) and CF3(a). I(a) desorbs as atomic I. CF3(a) dissociates in sequence, producing gas phase SiF2 and SiF4 and a carbon deposit on the surface. In the case of CF3CH2I, the C–I bond dissociation generates I(a) and CF3CH2(a). CF3CH2(a) undergoes β–F elimination to form gas phase CF2CH2 as well as further decomposition on the surface. At higher temperatures H2, I, HI, and SiF2 desorb and carbon deposits on the surface. © 1995 American Vacuum Society View full abstract»

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  • Surface free energies for diamond growth from hydrogen–hydrocarbon mixtures

    Page(s): 183 - 187
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    The surface free energies of diamond crystals under different chemical vapor deposition conditions have been comprehensively calculated. The calculations are based on a model where a fraction of carbon dangling bonds on the growth surface are saturated by hydrogen atoms. The results show that the surface free energies increase with the increasing substrate temperature or the decreasing hydrocarbon concentration in hydrogen and intersect each other at a critical point when the surface coverage fraction is equal to 0.83 monolayers. The results are excellent in theoretically interpretating the changes of predominant facets in the surface morphology from {100} to {111} with the increasing substrate temperature or the decreasing hydrocarbon concentration in hydrogen. © 1995 American Vacuum Society View full abstract»

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  • A sensitive method for measuring adsorbed carbon on palladium surfaces: Titration by NO

    Page(s): 188 - 194
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    Small quantities of adsorbed C have been deposited on Pd(112) by the dissociative adsorption of C2H4. It is demonstrated that although Auger electron spectroscopy is insensitive to the presence of this C(ads), temperature programmed desorption (TPD) can be used to determine the cleanliness of the surface. TPD spectra following the 300 K adsorption of 15NO on C‐covered Pd(112) indicate that reactive chemistry occurs during heating, as evidenced by the production of high temperature 15N2 (≊590 K) and CO (≊520 K) thermal desorption features. The results of this study are used to formulate an improved method for the removal of C from Pd surfaces in ultrahigh vacuum. © 1995 American Vacuum Society View full abstract»

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  • Positive and negative direct current bias effects on the microstructures and physical properties of hydrogenated amorphous carbon films prepared by radio frequency plasma chemical vapor deposition

    Page(s): 195 - 199
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    Positive and negative direct current (dc) bias effects were investigated for the synthesis of hydrogenated amorphous carbon films in radio frequency plasma chemical vapor deposition at 0.025 Torr and 200 °C. The applied bias ranged from +250 to -500 V. Both the positive and negative dc bias effects are discussed on the basis of surface and cross‐sectional morphology by scanning electron microscopy, deposition rate, threshold energy for photoelectron emission, contact angle, and adhesive strength of these films. For a negative bias, the surface of the film is very flat. The surface of the film deposited with no bias is somewhat pebbly while that of the film deposited with a positive bias is very rough and shows the presence of pores in the cross section. A negative bias substantially increases the deposition rate, refractive index, wettability, and adhesive strength. With no bias (ground potential), as compared to with a positive bias, there is a little increase in the wettability and adhesive force. The no bias case did not affect the properties arising from structural change, such as refractive index (density) and threshold energy for photoelectron emission (incorporated hydrogen). A positive bias did not affect these physical properties of the hydrogenated amorphous carbon films. These positive, negative, and no bias effects depend on the kinds of collision species and their collision energy against the substrate in the radio frequency plasma according to the additional bias conditions. © 1995 American Vacuum Society View full abstract»

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  • Photoemission spectroscopy study of thin Cr overlayers on NH3/GaAs(100)

    Page(s): 200 - 206
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    The interface formation of Cr/NH3/GaAs(100) and its temperature dependence using synchrotron radiation photoemission and resonance photoemission spectroscopies have been investigated. We observed that at T=90 K the initial deposition of Cr stimulated nitridation of the GaAs substrate and subsequent interface reaction was characterized by Cr‐induced substrate disruption. Annealing of the thus formed interface to room temperature and above caused further Cr–GaAs reaction. The metallicity of the Cr overlayer was examined using constant initial‐state spectroscopy (CIS) of Cr 3d with Ei=1.7 eV below the Fermi level. The CIS spectra showed a maximum at the photon energy hν=50.0 eV followed by a second broad maximum centered at hν=56–58 eV depending on the stage of the interface formation. As the nominal Cr coverage increases from 1 to 10 Å, the valence band photoemission spectra show a shift of the Cr 3d band toward the Fermi level. At the same time, the second maximum in CIS gradually dominates over the first, suggesting the evolution of the Cr overlayer to a more metallic state. The sensitivity of the second maximum in its peak position and intensity to the density of states near the Fermi level indicates that this maximum likely results from many body electron interactions. The results show that CIS can provide valuable information about the transition of a thin overlayer to a metallic state. © 1995 American Vacuum Society   View full abstract»

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  • Structure and morphology of microprotrusions grown on Ar+‐sputtered InP

    Page(s): 207 - 215
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    Ar+ sputter‐induced microprotrusions on monocrystalline InP at -100 °C, room temperature, and 100 °C were investigated by scanning and transmission electron microscopy. On a target cooled down to -100 °C, the protrusions were of dual structure, having an amorphous layer thickly covering the monocrystalline core. At room temperature, the protrusions that formed involved randomly oriented domains at the tip area, suggesting a recrystallization process occurring under ion impact. Heating the target to 100 °C resulted in a dramatic change in protrusion morphology and structure. Typically, the protrusions on the heated target could be classified as fibrous or whiskerlike protrusions or short ones topped with metallic crystallites. Crystal growth processes thus appeared to be involved in sputtering at 100 °C. © 1995 American Vacuum Society View full abstract»

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  • Local order measurement in SnGe alloys and monolayer Sn films on Si with reflection electron energy loss spectrometry

    Page(s): 216 - 220
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    Measurements of local order are demonstrated in Sn‐containing alloys and epitaxial monolayer thickness films by analysis of extended‐edge energy loss fine structure (EXELFS) data obtained by reflection electron energy loss spectrometry (REELS). These measurements of short‐range order provide a complement to the chemical information obtained with REELS and long‐range order obtained using reflection high energy electron diffraction. The results suggest that EXELFS measurements are practical for samples mounted on the growth manipulator in a molecular beam epitaxy chamber. Advantages and limitations of reflection EXELFS are discussed. © 1995 American Vacuum Society View full abstract»

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  • Adsorption of TiCl4 on TiSi2: Application to silicide chemical vapor deposition

    Page(s): 221 - 229
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    The adsorption/desorption kinetics of TiCl4 on polycrystalline TiSi2 have been measured quantitatively by temperature‐programmed desorption in order to better understand the chemical vapor deposition of the silicide from TiCl4 and SiH4. For small exposures, only SiCl2 desorbs near 1150 K. The kinetics are second order with respect to surface chlorine, and the desorption activation energy Ed is 85±4 kcal/mol. As this state approaches saturation, SiCl2 desorbs from a second state near 700 K. The kinetics are also second order, but desorption occurs through a continuum of energetic pathways peaking at 57 kcal/mol. As this state saturates, a third desorption peak consisting of SiCl4 appears near 500 K. The kinetics are first order with respect to surface chlorine and also comprise a distribution of energetic pathways, which peak at 33 kcal/mol. Coadsorption studies with SiH4 were also performed. Surface chlorine appears to bond to Si, not Ti, on the surface. These kinetics are utilized to predictively model the chemical vapor deposition of TiSi2 thin films. © 1995 American Vacuum Society View full abstract»

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  • Low pressure chemical vapor deposition of InSb using neopentylstibine and trimethylindium

    Page(s): 230 - 236
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    Low pressure chemical vapor deposition of InSb using neo‐pentylstibine and trimethylindium has been studied with x‐ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy, Raman spectroscopy, and scanning electron microscopy (SEM). At 600 K, the InSb film with an In:Sb atomic ratio of 1 and a growth rate of ∼2 Å/min was formed on GaAs(110). The binding energies of the In and Sb 3d5/2 XPS peaks are in excellent agreement with those taken from InSb single crystal and amorphous samples. The He(II) ultraviolet photoelectron spectrum also agrees reasonably well with photoemission spectra taken from InSb using different photon beam sources. The corresponding Raman spectrum showed two phonon peaks at 179 (TO) and 190 (LO) cm-1, respectively, which are virtually identical to the Raman data reported for InSb single crystal samples. The XPS measurements suggested a three‐dimensional growth mechanism for the InSb film on GaAs(110), which was confirmed by the SEM measurement. However, at ∼800 Å thickness, the SEM picture showed a very smooth InSb film, with the presence of some uncovered holes corresponding to ∼3% of the total surface area. The substrate temperature effect on the film growth was also investigated. At temperatures below 400 K, film growth was very slow and the decomposition of NpSbH2 and TMIn seemed to be incomplete, whereas above 800 K, metal droplets were clearly visible by SEM. The optimal growth temperature lies at approximately 600–700 K. © 1995 American Vacuum Society View full abstract»

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  • Compositional and electrical properties of Si metal–oxide–semiconductor structure prepared by direct photoenhanced chemical vapor deposition using a deuterium lamp

    Page(s): 237 - 243
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    High quality SiO2 layers have been grown on (111) Si substrates by direct photoenhanced chemical vapor deposition using monosilane (SiH4) and oxygen (O2) as gas sources under irradiation of a deuterium lamp. The refractive index of the deposited oxide is 1.462 at 250 °C when the gas ratio (O2/SiH4) is 5. The measurements of the Fourier transform infrared spectrum, x‐ray photoelectron spectroscopy, and Auger electron spectroscopy show that the dominant components of the oxide are silicon and oxygen and the film is SiO2. Hysteresis free capacitance–voltage characteristics of the metal–oxide–semiconductor diode was observed. After low temperature postoxidation annealing, the minimum interface trap density is 1.5×1011 cm-2 eV-1, which is comparable to that of thermal oxidation. © 1995 American Vacuum Society View full abstract»

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  • Effect of the predecomposition of SiF4 on the properties of silicon dioxide deposited at low temperatures using SiF4/SiH4/N2O in a double‐plasma process

    Page(s): 244 - 247
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    A low‐temperature (250 °C) plasma deposition process has been developed to prepare silicon dioxide films using SiF4/SiH4/N2O discharge mixtures, decomposing in a separate glow discharge the SiF4 gas just before being fed into the reaction chamber. The deposition rate for these oxides can be higher than 500 Å/min. According to infrared transmittance measurements, the effect of the SiF4 predecomposition is to reduce the amount of hydrogen in the silicon dioxide films. Ellipsometric and chemical etch rate measurements show that films prepared by this approach have better structural properties than those deposited without predecomposing the SiF4 gas. These results suggest that, the silicon–fluorine radicals generated by the predecomposition of the SiF4 gas, change the deposition chemistry in such a way that hinders the incorporation of O–H groups in the films. © 1995 American Vacuum Society View full abstract»

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  • Beam and decomposition properties of copper‐containing metalorganic precursors and their use for CuO thin film preparation in chemical beam epitaxy

    Page(s): 248 - 254
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    The 2,2,6,6‐tetramethyl‐3,5‐heptanedionato and pivaloato precursors of copper have been investigated for their thermodynamic and gas‐phase properties. More specifically, time‐modulated mass spectroscopy has been used to determine the chemical compositions of the effusive beams of metalorganic precursors under various conditions, and to identify the thermal decomposition products resulting from breakdown of the effusive beam on a heated MgO(001) single‐crystal surface. From these results, their relative suitability for use in chemical beam epitaxy is compared. Also, copper oxide films have been grown in a chemical beam epitaxy system and their properties are discussed. © 1995 American Vacuum Society   View full abstract»

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  • Crystal orientation control of YBa2Cu3Oy thin films on MgO prepared by excimer laser ablation with CO2 laser irradiation

    Page(s): 255 - 259
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    Superconducting YBa2Cu3Oy (YBCO) thin films were prepared on a MgO (100) substrate by XeCl excimer laser ablation with CO2 laser irradiation. Control experiments of crystal orientation of YBCO thin films were carried out by varying the substrate temperature during deposition; c‐axis oriented YBCO film, a‐axis oriented YBCO film, and a‐axis oriented YBCO film on the c‐axis were obtained on the MgO (100) substrates. a‐axis oriented YBCO films normal to the MgO (100) substrate were fabricated using the modified self‐template method. © 1995 American Vacuum Society View full abstract»

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  • Deposition of silicon oxide onto polyethylene and polyethyleneterephthalate: An x‐ray photoelectron spectroscopy interfacial study

    Page(s): 260 - 267
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    X‐ray photoelectron spectroscopy (XPS) and scanning electron microscopy were used to study the physico–chemical interaction between evaporated silicon oxide and polymers. SiO1.5 was shown to deposit as clusters onto polyethylene, not covering the whole surface of the substrate. Argon, oxygen, and nitrogen plasma treatments were tested to improve the reactivity of polyethylene, but only nitrogen was found to be reactive enough to allow for a uniform layer of silicon oxide, as on polyethyleneterephthalate. The high resolution XPS study of the interface between nitrogen plasma treated polyethylene and in situ deposited silicon oxide showed the formation of silicon–oxygen–carbon or silicon–nitrogen–carbon bonds while silicon–carbon bonds were only observed with polyethyleneterephthalate. © 1995 American Vacuum Society View full abstract»

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  • Effects of water partial pressure on the activated electron beam evaporation process to deposit tin‐doped indium‐oxide films

    Page(s): 268 - 275
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    The effects of water partial pressure (PH2O) during deposition on the structural and electrical properties of tin‐doped indium‐oxide (ITO) films have been investigated on an activated electron beam evaporation process using an arc plasma generator. The resistivity of the films deposited at 180 °C increased with an increase in PH2O in terms of a decrease both in Hall mobility and carrier density. X‐ray diffraction and scanning electron microscope analyses showed that the ITO films deposited at higher PH2O consisted of a major portion of larger crystalline grains with smaller internal strain and a small portion of amorphous regions which is supposed to be at the interface between the film and the substrate. Plasma diagnostics by optical emission spectroscopy revealed that atomic hydrogen was generated by electron‐impact dissociation of H2O and that the activation of Ar or O2 was suppressed in the higher PH2O process, which resulted in the deposition of less oxidized and lower‐damaged ITO films. © 1995 American Vacuum Society View full abstract»

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  • Epitaxial growth of body‐centered‐cubic transition metal films and superlattices onto MgO (111), (011), and (001) substrates

    Page(s): 276 - 281
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    We demonstrate epitaxial growth of the bcc transition metals Nb, Mo, Fe, and Cr via sputtering onto single crystal MgO substrates. The epitaxial growth orientations are (011), (112), and (001) when grown onto MgO (111), (011), and (001), respectively. Further, we demonstrate that, under appropriate growth conditions, superlattices of these materials (e.g., Fe/Cr, Fe/V, and Mo/V) can be grown with the same epitaxial order as the films. © 1995 American Vacuum Society View full abstract»

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  • Influence of a heteroepitaxial interface with large lattice mismatch on the low temperature growth of a film

    Page(s): 282 - 288
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    We report on the influence of a heteroepitaxial interface Pb/Cu(100) on the growth of a Pb film at 150 K using helium beam scattering, low‐energy electron diffraction (LEED), and Auger electron spectroscopy. The large lattice mismatch, the difference in bonding strengths, and symmetry between substrate and film produce a rather complex growth pattern. The growth mode in the very early stage is strongly influenced by the Pb/Cu interface, evolving from ordered growth (first layer) to disordered growth (second and third layers) and ordered quasi‐layer‐by‐layer growth (from the fourth to the sixteenth layers). The LEED pattern shows the presence of Pb(111) exposed surfaces with domains rotated by 90°. The envelope of helium beam intensity reveals evidence of quantum size effects and of increasing interface width. The broadening of in‐phase diffraction profiles indicates formation of mosaic surface structures. Better layer‐by‐layer growth is achieved by annealing the disordered second layer. Depending on substrate temperature, first layers with different structures are obtained. These first layer structures dramatically affect the subsequent growth at low temperature. © 1995 American Vacuum Society View full abstract»

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  • Interface structure of Ge/Si(111) during solid‐phase epitaxy studied by medium‐energy ion scattering

    Page(s): 289 - 294
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    The interface structure between a Ge thin film and Si(111) substrate during solid‐phase epitaxy of Ge is studied by medium‐energy ion scattering. Intermixing within the bilayer between the two‐dimensional Ge layer with the critical thickness of 4 monolayers (ML) and the Si substrate occurs at 550 °C and above. The intermixing advances into deeper layers with annealing at higher temperatures, and Si atoms from the substrate migrate to the uppermost surface above 770 °C. When Ge is deposited, in excess of the critical thickness, three‐dimensional islands form on the two‐dimensional layer with a thickness of 4 ML before intermixing between Ge and Si layers begins. Atomic displacement is observed in both the Ge film and the substrate near the interface. The substrate is compressed vertically about 1.2%. However, the strain caused by the lattice mismatch between Ge and Si is relaxed by intermixing, so atomic displacement is partially restored. © 1995 American Vacuum Society View full abstract»

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  • Growth, structural characterization, and stability of thin Cr/δ ‐Mn(001) superlattices

    Page(s): 295 - 300
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    We report on the epitaxial growth of Mn in the bcc high temperature modification δ‐Mn on Cr(001) surfaces at room temperature using molecular‐beam epitaxy (MBE). The growth of the individual layers can be well fitted by the layer‐by‐layer mode, and the Cr/Mn system forms separate layers. Cr/δ‐Mn(001) superlattices with equal individual layer thicknesses show an increase of the average lattice parameter c with increasing superlattice spacing Λ, with a maximum stretching of 4% at layer thickness of about 11.5 Å each compared to the bulk value of Cr. A stretching of 6% was found for a Ge(001)Fe20(Cr30Mn7)×12.5 superlattice with different individual layer thicknesses. The in‐plane lattice parameters are not affected with varying layer thicknesses. Increasing Mn‐layer thicknesses to values larger than ≊23 Å lead to a phase transition of the δ‐Mn. These results were obtained by means of Auger electron spectroscopy, reflection high energy electron diffraction, and x‐ray diffraction. © 1995 American Vacuum Society View full abstract»

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  • Epitaxial growth of ultrathin MgO films on Fe(001) seed layers

    Page(s): 301 - 304
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    Ultrathin films of MgO (5–300 Å ) were grown epitaxially onto 150‐Å‐thick Fe(001) seed layers on MgO(001) at 700 K using electron beam deposition. Reflection high‐energy and low‐energy electron diffraction and x‐ray photoelectron diffraction show that the films have good crystalline quality that improves with thickness. © 1995 American Vacuum Society View full abstract»

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  • Ion beam epitaxy of silicon films in an ultrahigh vacuum using a sputtering‐type metal ion source

    Page(s): 305 - 313
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    Ion beam epitaxy (IBE) of silicon films in an ultrahigh vacuum is carried out using a specially developed electric‐mirror sputtering‐type metal ion source. Silicon films with 2×1 reconstructed surface structures are homoepitaxially grown on silicon wafers above 320 °C, and contamination by oxygen and carbon is suppressed below the level of bulk Czochralski silicon (≪1×1018 cm-3). Argon entrapment from sputtering discharge in the film is suppressed by controlling the ion energy during film growth, and metal contamination is suppressed below the detection limit (≪1×1016 cm-3) of the conventional secondary ion mass spectroscopy system used. The IBE films exhibit bulklike perfect crystallinity, as examined by electron microscopy, etch‐pit observation, Raman spectroscopy, and Rutherford backscattering spectroscopy. Precise and steep control of dopant profile is demonstrated in situ. Heavily doped (B:5×1018 cm-3, As: 1×1019 cm-3) silicon films are grown and the dopants are ideally activated in the films. These films exhibit bulklike carrier mobility. © 1995 American Vacuum Society View full abstract»

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  • Thermal relaxation kinetics of strained Si/Si1-xGex heterostructures determined by direct measurement of mosaicity and lattice parameter variations

    Page(s): 314 - 326
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    The thermal stability of strained Si1-xGex/Si heterostructures grown by molecular‐beam epitaxy was investigated. Alloy structures with Ge fractions between 5% and 23% and thicknesses from 160 to 200 nm, corresponding to excess stress from 112 to 712 MPa, were grown at 450 °C. X‐ray high‐resolution reciprocal lattice mapping (HRRLM) was employed as the major analysis tool to investigate the status of the strain and the material quality of the structures prior to and after high‐temperature furnace annealing between 700 and 1000 °C. By this technique, the variations of the alloy lattice parameters parallel and perpendicular to the growth direction were independently determined as functions of the annealing temperature (Ta) within an accuracy ≊10-5. In addition, the annealing‐induced variations in the shape of the x‐ray scattering distributions were used to investigate the material quality and the changes in the mosaic character of the structures. For 700≤Ta≤800 °C, a strong increase in the strain relaxation with an activation energy of (2.3±0.2) eV was observed. The relaxation dependence on the excess stress was determined to follow a power of (1.9±0.2) law. In addition, strong broadening of the diffraction peaks was observed in the direction orthogonal to the scattering vector, demonstrating that the formation of strain‐relieving dislocations introduces significant mosaicity in the structures. At Ta≳800 °C, the levels of strain relaxation and mosaicity were found to be high, but the rate of increase was clearly reduced. The contribution to this effect owing to the dislocation–dislocation interaction was evaluated and was shown to be an important mechanism in limiting the maximum attainable relaxation in the structures. Effects of Ge diffusion- - were estimated and were shown to be relevant at Ta=1000 °C. The relaxation was significantly higher for structures with a higher Ge fraction but, in a structure with 5.67% Ge, a low‐intensity diffuse scattering probably related to local strain fields from the initial stages of relaxation and dislocation formation, was observed. The use of HRRLM in the characterization of this important heterostructure system appeared to be appropriate not only for providing an accurate determination of lattice parameter variations as a function of Ta but, in addition, for differentiating between the effects of strain character and those of defect‐related contributions to Bragg reflections. © 1995 American Vacuum Society View full abstract»

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  • Charge separation in an electron cyclotron resonance plasma

    Page(s): 327 - 331
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    Separation of an electron cyclotron resonance (ECR) plasma flux into an ion flux and an electron flux during plasma extraction has been investigated. The phenomenon is explained by the difference between ion current distribution and electron current distribution in the ECR plasma. When magnetic force lines cross the direction of the electron flux at a larger angle, the charged particle flux separation is enhanced. Also, evaluation of the flux diffusion equation for a magnetoplasma indicates that the diffusion coefficient of the electron flux across the force lines is much smaller than that of the ion flux. The ion flux diffuses isotropically compared to the electron flux confined by the magnetic field, resulting in charged particle flux separation. The potential distribution within a wafer exposed to the ECR plasma was evaluated by the flat band voltage (Vfb) shifts in metal–nitride–oxide semiconductor capacitors. The separation of the charged particle flux causes a nonuniform potential distribution within the wafer. © 1995 American Vacuum Society 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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Editor
G. Lucovsky
North Carolina State University