Search Results - (Author, Cooperation:Rusli)

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  1. 1
    Chew, K. ; Rusli ; Yoon, S. F. ; Ahn, J. ; Zhang, Q. ; Ligatchev, V.

    [S.l.] : American Institute of Physics (AIP)
    Published 2002
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    The density of gap states distribution in silicon (Si) rich hydrogenated amorphous silicon carbide (a-Si1−xCx:H) films with varying carbon (C) fraction (x) is investigated by the photothermal deflection spectroscopy (PDS). The films are grown using the Electron Cyclotron Resonance Chemical Vapor Deposition (ECR-CVD) technique. By using different methane-to-silane gas flow ratios, a-Si1−xCx:H with x ranging from 0 to 0.36 are obtained. A deconvolution procedure is performed based on a proposed DOS model for these Si rich a-Si1−xCx:H. Good fits between the simulated and experimental spectra are achieved, thus rendering support to the model proposed. Deduction of the DOS enables us to obtain various parameters, including the optical gap and the valence band tail width. The fitted mobility gap Eg is found to be well correlated to the Tauc gap Etauc and E04 gap deduced from the optical absorption spectra. A correlation is also seen between the fitted valence band tail width Evu, the Urbach energy Eu and the defect density. All these parameters are seen to increase with C alloying. A shift in the defect energy level in the midgap with increasing C incorporation is observed, together with a broadening of the defect distribution and a stronger correlation between the defect bands, which can be accounted for in terms of the influence of C dangling bonds on the deep defect density distribution. © 2002 American Institute of Physics.
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  2. 2
    Yoon, S. F. ; Tan, K. H. ; Rusli ; Ahn, J.

    [S.l.] : American Institute of Physics (AIP)
    Published 2002
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    Diamond-like carbon (DLC) films were deposited using the electron cyclotron resonance (ECR) chemical vapor deposition process. The behavior of the ECR plasma was formulated using deposition conditions such as microwave power, pressure, and hydrogen/methane (H2/CH4) ratio as input parameters. Thereafter, the outputs were used to formulate a DLC film deposition model, which takes into account the ion bombardment at the film surface, attachment of carbon-carrying ions, and chemisorption of hydrocarbon radicals on the film and hydrogen–surface reactions. The DLC film deposition model suggests that under conditions of high hydrogen atom flux, the main precursors are carbon-carrying ions. Hydrocarbon radicals, such as CH3, only contribute to ∼20% of the total film deposition rate. © 2002 American Institute of Physics.
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  3. 3
    Yu, J. ; Ahn, J. ; Zhang, Q. ; Yoon, S. F. ; Rusli ; Li, Y. J. ; Gan, B. ; Chew, K. ; Tan, K. H.

    [S.l.] : American Institute of Physics (AIP)
    Published 2002
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    Carbon nanoparticles were prepared from H2 and CH4 by microwave plasma chemical vapor deposition at various temperatures as low as 250 °C by using nickel and iron as catalysts. The carbon nanoparticles are well graphitized until a temperature as low as 400 °C, and the degree of graphitization increases with increasing growth temperature. Field emission measurements showed that the carbon nanoparticles are excellent electron field emitters, comparable to carbon nanotubes. Field emission properties became better with increasing growth temperature, and the threshold fields of the carbon nanoparticles deposited at 400, 500, 670 °C, were 3.2, 3, and 1 V/μm, respectively. No emission was observed for the carbon nanoparticles deposited below 400 °C. The low threshold field of the carbon nanoparticles is attributed to field enhancement effect and the higher degree of graphitization. © 2002 American Institute of Physics.
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  4. 4
    Cui, J. ; Rusli ; Yoon, S. F. ; Yu, M. B. ; Chew, K. ; Ahn, J. ; Zhang, Q.

    [S.l.] : American Institute of Physics (AIP)
    Published 2001
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    Hydrogenated amorphous silicon carbide (a-Si1−xCx:H) films have been deposited using an electron cyclotron resonance chemical vapor deposition system. The effects of varying the microwave power from 100 to 1000 W on the deposition rate, optical band gap, film composition, and disorder were studied using various techniques such as Rutherford backscattering spectrometry, spectrophotometry, Fourier-transform infrared absorption, and Raman scattering. Samples deposited at 100 W are found to have a carbon fraction (x) of 0.49 which is close to that of stoichiometric SiC, whereas samples deposited at higher microwave powers are carbon rich with x which are nearly independent of the microwave power. The optical gaps of the films deposited at higher microwave powers were noted to be related to the strength of the C–Hn bond in the films. The photoluminescence (PL) peak emission energy and bandwidth of these films were investigated at different excitation energies (Eex) and correlated to their optical band gaps and Urbach tail widths. Using an Eex of 3.41 eV, the PL peak energy was found to range from 2.44 to 2.79 eV, with the lowest value corresponded to an intermediate microwave power of 600 W. At increasing optical gap, the PL peak energy was found to be blueshifted, accompanied by a narrowing of the bandwidth. Similar blueshift was also observed at increasing Eex, but in this case accompanied by a broadening of the bandwidth. These results can be explained using a PL model for amorphous semiconductors based on tail-to-tail states radiative recombination. A linear relation between the full width at half maximum of the PL spectra and the Urbach energy was also observed, suggesting the broadening of the band tail states as the main factor that contributes to the shape of the PL spectra observed. © 2001 American Institute of Physics.
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  5. 5
    Cui, J. ; Rusli ; Yoon, S. F.

    [S.l.] : American Institute of Physics (AIP)
    Published 2001
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    Hydrogenated amorphous silicon carbide (a-Si1−xCx:H) films have been deposited using the electron cyclotron resonance chemical vapor deposition process under varying negative rf-bias voltage at the substrate. The optical and structural properties of these films are characterized using Rutherford backscattering spectroscopy, transmittance/reflectance spectrophotometry, photothermal deflection spectroscopy, Fourier transform infrared absorption, Raman scattering, and room temperature photoluminescence (PL). These films deposited using a gas mixture of silane, methane, and hydrogen at a constant gas flow ratio showed a slight increase in the carbon fraction x, but very obvious structural transformation, at increasing rf induced bias voltage from −20 to −120 V. Near stoichiometric a-Si1−xCx:H films with a carbon fraction x of almost 0.5 are achieved at low bias voltage range from −20 to −60 V. Visible PL with relatively low efficiency can be observed from such films at room temperature. For larger bias voltages from −80 to −120 V, slightly C-rich a-Si1−xCx:H films (x〉0.5) with larger optical gaps are obtained. These films have relatively higher PL efficiency, and the relative quantum efficiency was also found to depend strongly on the optical gap. Structurally, it was found that there is an increase in the hydrogen content and carbon sp2 bonding in the films at larger bias voltages. The latter leads to an increase in the disorder in the films. The linear relationship observed between the Urbach energy E0 and B factor in the Tauc equation suggests that the local defects related to microstructural disorder resulting from alloying with carbon dominate the overall defect structure of the films. Substrate biasing is noted to be crucial for the formation of Si–C bonds, as deduced from the Raman scattering results. © 2001 American Institute of Physics.
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  6. 6
    Huang, Q. F. ; Yoon, S. F. ; Rusli ; Chew, K. ; Ahn, J.

    [S.l.] : American Institute of Physics (AIP)
    Published 2001
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    Metal-containing carbon (Me-C:H) films were deposited using the electron cyclotron resonance chemical vapor deposition technique in conjunction with a metal screen-grid system. Four sets of Me-C:H films were analyzed using Raman scattering. Two sets were molybdenum-containing carbon (Mo-C:H) films deposited at fixed dc bias (at different CH4/Ar ratios), and at fixed CH4/Ar ratio (at different dc bias). Another two sets of nickel-containing carbon (Ni-C:H) films were deposited at fixed rf power, but at a different CH4/Ar ratio, with and without postgrowth thermal annealing at 200 °C. All films showed the characteristic G and D peaks except for those with high metal content. The D peak is very pronounced in the Ni-C:H films, and both the G and D peaks follow an opposite trend; downshifting and upshifting in wave number, respectively, as the CH4/Ar ratio was increased. In the case of Mo-C:H films deposited at fixed dc bias, both peaks downshifted in wave number, following an increase in the CH4/Ar ratio. The G peak full width at half maximum for both the Ni- and Mo-C:H films increased slightly with an increase in CH4/Ar ratio, consistent with the variation in the relative integrated intensity of the D to G peak (ID/IG). Thermal annealing experiments conducted on the film samples revealed relatively stable characteristics with a minor effect on the film structure. The results showed that the impinging ion energy plays an important role in the structural properties of the Me-C:H films. © 2001 American Institute of Physics.
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  7. 7
    Yoon, S. F. ; Tan, K. H. ; Rusli ; Ahn, J. ; Huang, Q. F.

    [S.l.] : American Institute of Physics (AIP)
    Published 2001
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    Diamond-like carbon films were deposited using electron cyclotron resonance (ECR) chemical vapor deposition incorporated with a screen grid under different dc bias voltages to compare the effect of ion density and ion energy on the film properties. Langmuir probe measurements and optical emission spectroscopy were used to characterize the ECR plasma, while the films were characterized using Raman and infrared (IR) spectroscopies, hardness, and optical gap measurements. The plasma measurements showed that the ion density, hydrogen atom density, and CH density decreased monotonously following increase in the dc bias voltage. Raman spectra and optical gap measurements indicate the films became more graphitic with lower content of sp3-hybridized carbon atoms as the dc bias voltage was increased. An increase in hydrogen content was found in films prepared at relatively high dc bias voltage, as indicated by IR measurements. Films deposited at −150 V exhibit maximum hardness. The results show the ion density has a stronger effect on the film deposition rate and hydrogen content, while the ion energy affects the film properties more predominantly by changing the bonding structure. © 2001 American Institute of Physics.
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  8. 8
    Yu, M. B. ; Rusli ; Yoon, S. F.

    [S.l.] : American Institute of Physics (AIP)
    Published 2000
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    Nanocrystalline cubic silicon carbide (3C–SiC) films embedded in an amorphous SiC matrix were fabricated by the hot-filament chemical-vapor-deposition technique using methane and silane as reactance gases. High-resolution transmission electron micrographs clearly showed that these films contain naoncrystallites, with an average dimension of about 7 nm, embedded within an amorphous matrix. X-ray photoelectron spectroscopy, x-ray diffraction, infrared absorption, and Raman scattering studies revealed the nanocrystallites as having the structure of that of 3C–SiC. In contrast to 3C–SiC, where no photoluminescence could be observed at room temperature, strong visible emission with a peak energy of 2.2 eV could be seen from the nanocrystalline films at room temperature. The presence of nanocrystalline cubic SiC in these films is believed to result in a change in their energy-band structure, compared to that of 3C–SiC, which promotes radiative recombination of electron–hole pairs. © 2000 American Institute of Physics.
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  9. 9
    Yoon, S. F. ; Huang, Q. F. ; Rusli ; Yang, H. ; Ahn, J. ; Zhang, Q.

    [S.l.] : American Institute of Physics (AIP)
    Published 1999
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    Results from x-ray photoelectron spectroscopy (XPS) measurements of molybdenum-containing carbon films (Mo–C:H) deposited using an electron cyclotron resonance chemical vapor deposition (ECR-CVD) system are reported in this article. The Mo–C:H films were deposited using a technique with two Mo screen grids incorporated inside the ECR-CVD chamber. The versatility of this technique arises from the ability to control the degree of plasma ionization, sputtering rate of the metal grids, and energy of the impinging ions. Variation of the (CH4/Ar) gas flow ratio results in a change of the Mo fraction within the range of 0.32–15.11 at. %. For large amounts of Mo, the C 1s peak was split into four components with binding energies of 283.05, 284.67, 286.22, and 288.17 eV. These were identified as carbidic (metallic), polymeric, and oxidic (single- and double-bond) carbon, respectively. The presence of oxygen was detected in the films, due possibly to free-radical absorption at the film surface during deposition, or oxidation of the metallic Mo at the surface upon exposure to atmosphere. The results showed that the ECR-CVD technique is useful and effective for the deposition of Mo–C:H films with low- and high-Mo content. © 1999 American Institute of Physics.
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  10. 10
    Higuchi-Rusli, Ronnie

    [S.l.] : American Institute of Physics (AIP)
    Published 1995
    Staff View
    ISSN:
    1089-7623
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Electrical Engineering, Measurement and Control Technology
    Notes:
    The characteristics of a PdB liquid metal ion source have been investigated in terms of its energy spread, current voltage, and total energy distribution. The beam energy spread increases with ion source applied voltage and species mass. The total energy distribution curve exhibits full width at half maximum increase from 20 to 26 eV as the total current increases from 6 to 25 μA. The energy spread of the heavy isotope, 106Pd+, is 44 eV at an extractor applied voltage of 8.5 keV. The energy spread of 11B+ is observed to saturate at high total current (or high extractor applied voltage). This implies that beyond 8.5 keV, the energy spread of 11B+ is independent of applied voltage. Throughout the measurement, the energy spread remained a Gaussian distribution which is an inherent characteristic of sources with Taylor cone formation. © 1995 American Institute of Physics.
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  11. 11
    Higuchi-Rusli, Ronnie H.

    [S.l.] : American Institute of Physics (AIP)
    Published 1996
    Staff View
    ISSN:
    1089-7623
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Electrical Engineering, Measurement and Control Technology
    Notes:
    Characteristics of AuSi liquid metal alloy ion source with single and coupling (double) extractor electrodes have been investigated both in the focused ion beam machine, and in the vacuum test bed system equipped with quadrupole mass spectrometer. Liquid metal ion source with coupling extractor electrode produce a stable total ion current which increases almost linearly when compared with a single extractor electrode. The isotope current of 197Au+ observed with quadrupole mass spectrometer is higher in the ion source with coupling extractor electrode than in a single extractor electrode, nonetheless, the pattern of its current–voltage characteristics remain the same for both single and coupling extractor electrodes. However, for lighter isotopes such as 28Si+ and 28Si++, the result is reversed (higher in ion source with single extractor electrode). The secondary electron image of copper grid pictures obtained from focused ion beam systems installed with an AuSi liquid metal alloy ion source with single and coupling extractor electrodes remain the same. © 1996 American Institute of Physics.
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  12. 12
    Rusli ; Robertson, J. ; Amaratunga, G. A. J.

    [S.l.] : American Institute of Physics (AIP)
    Published 1996
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    The photoluminescence (PL) of amorphous hydrogenated carbon (a-C:H) has been investigated as a function of optical gap and excitation energy. The PL spectra exhibit a red shift when the excitation energy falls below the optical gap. The bandwidth of the PL spectra increases with the excitation energy but depends very weakly on the gap. The results are discussed in terms of the electronic structure of a-C:H and the configuration of sp2 sites. It is proposed that PL arises by the geminate radiative recombination of the electron–hole pairs confined to the π states of the sp2 bonded clusters. The quantum efficiency is found not to decrease for excitation above the gap, indicating that the electron–hole pair remain bound, and suggesting that any mobility edges lie beyond the optical band edges. The PL efficiency is found to increase roughly exponentially with optical gap, displaying two regimes. At higher gap the efficiency depends just on the gap, while at lower gap the dependence may depend on the capture radius of nonradiative recombination centers. © 1996 American Institute of Physics.
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  13. 13
    Zhang, Qing ; Yoon, S. F. ; Rusli ; Yang, H. ; Ahn, J.

    [S.l.] : American Institute of Physics (AIP)
    Published 1998
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    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    Influence of oxygen on the thermal stability of amorphous hydrogenated carbon (a-C:H) films is investigated by annealing the films at 520, 610, and 670 K in vacuum and in O2 flow, respectively. The a-C:H films used for this study were deposited using microwave plasma from a mixture of 10 sccm pure methane and 100 sccm hydrogen in an electron cyclotron resonance chemical vapor deposition system. It is found that the anneals in O2 gas flow lead to much more prominent variation in film thickness, optical band gap, and IR absorption related to C–H stretching vibration than the anneals in vacuum. Raman scattering and optical absorption indicate that O2 greatly promotes the transformation from polymeric to graphitic microstructure with increasing annealing temperature. Possible conversion of bond structure and the role of O2 in the stability of the films are discussed. © 1998 American Institute of Physics.
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  14. 14
    Zhang, Qing ; Yoon, S. F. ; Rusli ; Ahn, J. ; Yang, H.

    [S.l.] : American Institute of Physics (AIP)
    Published 1998
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    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    In this article we studied the influence of bombardment energy of hydrocarbon ions on the properties of hydrogenated diamond-like carbon (DLC) films using x-ray reflectivity, Raman spectroscopy, and Fourier-transform infrared. The DLC films were prepared with an electron cyclotron resonance system using H2 and CH4 gases and the ion energy was tunable through a rf-induced dc bias voltage. It was observed that the surface roughness is increased and C–H bonded hydrogen concentration is decreased with increased ion energy, whereas the mass density, hardness, and sp3/sp2 ratio exhibited optimum values. A thin SiC layer was found to form between the DLC films and silicon substrates. Two proposed carbon deposition mechanisms, i.e., the shallow implantation (subplantation) model and the adsorbed layer model, are examined based on the results obtained in this study. Our results indicate that ion bombardment energy is a critical factor in determining the film properties and the ion subplantation could be an important deposition process even for hydrogenated DLC films. © 1998 American Institute of Physics.
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  15. 15
    Higuchi-Rusli, R. H. ; Corelli, J. C.

    Woodbury, NY : American Institute of Physics (AIP)
    Published 1987
    Staff View
    ISSN:
    1077-3118
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    It has been found that by utilizing a sharp needle for the extractor electrode in close proximity to the source tip wetted with Cu3P liquid alloy, a large increase (factor ∼300) in ion current is observed in comparison to standard liquid metal ion sources (LMIS's). In standard previously used LMIS's the extractor electrode was a flat plane with a circular hole centered on the source needle tip. This new high current source has important applications in focused and broad ion beam deposition systems.
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  16. 16
    Yoon, S. F. ; Tan, K. H. ; Rusli ; Ahn, J.

    [S.l.] : American Institute of Physics (AIP)
    Published 2002
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    Diamond-like carbon films were deposited using the electron cyclotron resonance chemical vapor deposition (ECR-CVD) system. A model for the ECR plasma was formulated using deposition parameters, such as microwave power, pressure, and hydrogen/methane ratio as inputs. Using the model, electron energy, rate constant of electron impact reactions, and density of species in the plasma are calculated. The outputs of the model are analyzed as a function of deposition conditions, such as microwave power, pressure, and hydrogen/methane ratio and compared to experimental data measured using a Langmuir probe. The results show that ion density increases following the increase in microwave power and hydrogen/methane ratio, and decreases following the increase pressure. Results from the model are in agreement with experimental data, and show that the main neutral species are H2, CH4, H, CH3, CH, C2H5, CH2, and C2H6. The main ionic species are H2+, CH4+, CH3+, CH2+, H+, CH5+, C2H4+, C2H5+, and CH+. © 2002 American Institute of Physics.
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  17. 17
    Gan, Bo ; Ahn, J. ; Rusli ; Zhang, Qing ; Yoon, S. F. ; Ligatchev, V. A. ; Yu, J. ; Chew, K. ; Huang, Q.-F.

    [S.l.] : American Institute of Physics (AIP)
    Published 2001
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    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    Structural and electrical characteristics of chemical vapor deposited (CVD) diamond films have been studied as a function of film thickness. The samples comprise a set of codeposited, nominally undoped diamond films with average grain size on the growth surface increasing linearly with the film thickness. Raman scattering analysis reveals a decrease of nondiamond phase and intragrain defects with increasing film thickness. Temperature dependent dc conductivity results indicate that, as the film thickness increases, the Fermi level moves towards the valence band. There is a corresponding decrease in the density of states at the Fermi level, as deduced from the space-charge-limited current in the bulk of the samples. The spatial variation in the density of states through the material closely reflects the changes observed in the structural and electrical properties of the films. Such characteristic has the implication on the application of CVD diamond in the area of electronics. © 2001 American Institute of Physics.
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  18. 18
    Huang, Q. F. ; Yoon, S. F. ; Rusli ; Yang, H. ; Gan, B. ; Chew, Kerlit ; Ahn, J.

    [S.l.] : American Institute of Physics (AIP)
    Published 2000
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    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    The conduction mechanism of molybdenum-containing (Mo) diamond-like carbon films deposited using electron cyclotron resonance chemical vapor deposition was investigated. It is found that there is a conductivity turning point at around 115 K, above which the conductivity is strongly temperature dependent. This indicates that two types of conduction mechanisms, thermal activation and tunneling coexist in the films, and they dominate the conduction behavior in the high and low temperature regimes, respectively. Within the temperature range investigated, the Poole–Frenkel effect is to be expected for thermal activation. However, due to the low concentration of Mo in the films, this effect was not observable. Tunneling is thought to occur between the Mo clusters or the sp2 clusters. A conductivity model, based on the thermal activation and tunneling, is proposed, and showed good agreement with the results obtained at low field. The conduction behavior at high field is also discussed and some possible mechanisms are proposed. © 2000 American Institute of Physics.
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  19. 19
    Rusli ; Yoon, S. F. ; Huang, Q. F. ; Yang, H. ; Yu, M. B. ; Ahn, J. ; Zhang, Q.

    [S.l.] : American Institute of Physics (AIP)
    Published 2000
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    We have recently proposed a technique for depositing metal incorporated carbon films (Me–C:H) based on an electron cyclotron resonance chemical vapor deposition (ECR) process. This technique employs an ECR plasma derived from the excitation of source gases CH4 and Ar, together with two grids embedded within the chamber that serve as the source of the metal. It has been successfully applied for the deposition of tungsten–carbon films (W–C:H) which have been shown to exhibit a wide range of electrical, optical, and microstructural properties. These properties can be controlled through varying the deposition conditions such as the bias voltages at the grids and the substrate holder, and the flow ratio of CH4/Ar. In this work, we report on the growth and characterization of molybdenum–carbon (Mo–C:H) films deposited using the above technique incorporating two pure Mo grids. The effect of radio-frequency induced direct-current (dc) bias at the substrates was investigated. It was found that the resistivity of the films decreased by 9 orders of magnitude, and the optical gap decreased by more than 2 eV with increasing bias voltage from −38 to −130 V. The results suggest that the substrate dc bias has a crucial effect on the incorporation of Mo into the a-C:H films and the resulting microstructures, with larger bias voltages leading to an increase in the Mo fractions in the films. Concurrently, the hardness of the films was found to deteriorate from 22 to 10 GPa. The structures of these Mo–C:H films were characterized using x-ray diffraction and Raman scattering. Mo was found to exist in the forms of Mo and MoC and Mo2C. The experimental results are interpreted in terms of the effects of ion energy on the structure of the films having Mo clusters embedded within an amorphous carbon matrix. © 2000 American Institute of Physics.
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  20. 20
    Zhang, Qing ; Yoon, S. F. ; Rusli ; Ahn, J. ; Yang, H.

    [S.l.] : American Institute of Physics (AIP)
    Published 1999
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    X-ray reflectivity under grazing incidence conditions is a powerful technique to study thin film density, surface roughness, and the multilayer structure without destroying the samples. In this article, we, using x-ray reflectivity technique, have studied the effects of bias voltage and deposition pressure on the mass density, surface and interface roughness of hydrogenated diamond-like carbon (DLC) films. It is observed that the surface roughness increases with increasing the bias voltage and with decreasing the deposition pressure over a wide range. The mass density, hardness and sp3/sp2 ratio deduced from the Raman spectra pass through their maximal values with the bias voltage, while they are increased monotonously with the pressure. A thin SiC layer is found to be formed between the DLC films and silicon substrate. According to our results, the influences of the bias voltage and deposition pressure on the film properties are clearly reflected through hydrocarbon ion energy impinging on the growing surface. Based on the film surface feature as a function of the ion energy, we suggest that the shallow ion implantation (subplantation) process could be a dominant deposition mechanism. © 1999 American Institute of Physics.
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