Browsing by Author "CHEN, WH"

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CHARACTERIZATIONS OF OXIDE GROWN BY N2O
(1993-10-01)
CHAO, TS
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CHEN, WH
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SUN, SC
;
CHANG, HY
;
電控工程研究所
The constitution of N2O oxide has been investigated by using Auger analyses, ellipsometry measurement, and Fourier transform infrared (FTIR) spectroscopy in this paper. We found a nitrogen-rich layer formed at the interface of SiO2/Si by Auger analyses. From the results of ellipsometry, we found the thinner the N2O oxide, the larger the refractive index. A two-layer model construction of N2O oxide was proposed for modeling the interfacial layer. We found that this layer thickness is 14 to 20 angstrom when the refractive index was set to 1.77. FTIR analyses show that some of the Si-O bonds were replaced by Si-N bonds. This is the reason that N2O oxide has better electrical properties and a lower growth rate than those of the conventional dry 02 oxide.
DOUBLE FLUORESCENCE LIFETIMES OF METAL-FREE PHTHALOCYANINE IN A MIXED-SOLVENT SHPOLSKII MATRIX AT 4.2K
(1989-08-20)
CHEN, WH
;
RIECKHOFF, KE
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VOIGT, EM
;
THEWALT, MLW
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電子物理學系
EFFECTS OF SIH4, GEH4, AND B2H6 ON THE NUCLEATION AND DEPOSITION OF POLYCRYSTALLINE SI1-XGEX FILMS
(1994-09-01)
LIN, HC
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CHANG, CY
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CHEN, WH
;
TSAI, WC
;
CHANG, TC
In this study, the effects of different reactants, namely, SiH4, GeH4 and B2H6, on the nucleation and deposition of polycrystalline silicon-germanium (poly-Si1-xGe(x)) films on oxide surface in an ultrahigh vacuum chemical vapor deposition reactor were explored. The results show that the addition of GeH4 tends to retard the nucleation process of poly films while B2H6 is preferential for adsorbing on the oxide surface. These effects lead to different incubation duration depending on the kind of reactants used. On the deposition of poly-Si1-xGe(x) films, it is observed that the Ge incorporation is only slightly related to the substrate type, but the deposition mode of poly-Si1-xGe(x) films is much different from that of epitaxial growth on Si(100). The incorporation of Ge atoms also overcomes the anomalous doping effect encountered in heavily boron-doped poly-Si films and allows extremely low resistivity (below 2 mOMEGA-cm) poly films to be obtained at low temperatures (less-than-or-equal-to550-degrees-C).
ELECTRONIC-SPECTRA AND PHOTOCHEMICAL TRANSFORMATION OF TERTIARY BUTYLPHTHALOCYANINE IN SHPOLSKII MATRICES
(1991)
CHEN, WH
;
HU, YY
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RIECKHOFF, KE
;
VOIGT, EM
;
電子物理學系
Electronic spectral properties of tertiary butylphthalocyanine (TBH2Pc) in a 4.2 K n-hexadecane (C-16) matrix were investigated. A clear doublet in the 0-0 fluorescence region was recorded, representing a approximately 20 cm-1 Stokes shift due to a different proton geometry (molecular tautomerism) in the centre of the molecule. Photochemical interconversion between the tautomers was studied by the intensity variation of fluorescence bands as a function of time. The transformation saturated in several tens to two hundreds of milliseconds under our pumping conditions. Similar investigations of the complex in solid n-octadecane (C18) were also carried out on a less detailed scale. The results were compared with those for free base phthalocyanine (H2Pc) in a mixed solvent matrix of alpha-chloronaphthalene (alpha-ClN) and n-octane (C-8).
ELECTRONIC-SPECTRA AND ZEEMAN EFFECT OF RUTHENIUM PHTHALOCYANINE IN SHPOLSKII MATRICES
(1989-10-10)
CHEN, WH
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HUANG, TH
;
RIECKHOFF, KE
;
VOIGT, EM
;
光電工程學系
FOURIER-TRANSFORM INFRARED SPECTROSCOPIC STUDY OF OXIDE-FILMS GROWN IN PURE N2O
(1995-05-01)
CHAO, TS
;
CHEN, WH
;
LEI, TF
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The properties of the oxide films grown by pure N2O were studied in this work. A two-layer model, considering a N2O oxide with an oxy-nitride film at the interface, was used to describe the dependence of the main peak shift in a Fourier transform infrared (FTIR) spectrum on N2O thicknesses. The thickness of interfacial layer was determined by FTIR and multiple-angle incident ellipsometer. Both methods showed consistent results and the thickness of this layer is found to be 14-16 Angstrom.
IMPROVEMENT OF THIN OXIDES THERMALLY GROWN ON THE REACTIVE-ION-ETCHED SILICON SUBSTRATES
(1995-05-01)
UENG, SY
;
WANG, PW
;
KANG, TK
;
CHAO, TS
;
CHEN, WH
Thin oxides thermally grown in reactive-ion-etched (RIE) silicon substrates in N2O and diluted O-2 ambient have been studied. The microroughness of the oxide-silicon interface was investigated using a spectrophotometer, atomic force microscopy (AFM), and cross-sectional high-resolution electron microscopy (HRTEM). The microroughness is strongly dependent on the RIE conditions and the post etching treatments. Furthermore, oxidation-enhanced interface microroughness has been observed. As compared with the pure oxides grown in diluted oxygen, N2O-grown oxides exhibit stronger immunity to RIE-induced damage. N2O oxidation of the etched specimens treated with an after-treatment-chamber (ATC) process result in the best electrical properties.
OPTICAL DATING STUDIES OF QUARTZ AND FELDSPAR SEDIMENT EXTRACTS
(1988)
GODFREYSMITH, DI
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HUNTLEY, DJ
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CHEN, WH
;
光電工程學系
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Department of Photonics
PHOTOCHEMICAL TRANSFORMATION OF METAL-FREE PHTHALOCYANINE IN A SHPOLSKII MATRIX
(1990)
CHEN, WH
;
RIECKHOFF, KE
;
VOIGT, EM
;
電子物理學系
;
Department of Electrophysics
SUPERIOR DAMAGE-IMMUNITY OF THIN OXIDES THERMALLY GROWN ON REACTIVE-ION-ETCHED SILICON SURFACE IN N2O AMBIENT
(1994-05-01)
UENG, SY
;
CHAO, TS
;
WANG, PJ
;
CHEN, WH
;
CHANG, DC
Thin oxides thermally grown on reactive-ion-etched silicon surfaces in N2O ambient have been studied. As compared with pure oxides grown on the etched silicon in dry oxygen, N2O-grown oxides exhibit significantly stronger immunity to the RIE-induced damages. A great improvement in both time-zero-dielectric-breakdown (TZDB) and time-dependent-breakdown (TDDB) characteristics is observed for the N2O-grown oxides on RIE-treated silicon surfaces. Accelerated tests have shown that the N2O oxide grown on the RIE silicon surface can achieve a lifetime longer than the pure oxide grown on the correspondingly etched silicon surface with a factor over 10(8).
TAUTOMERIC RELAXATION RATES IN THE GROUND-STATE OF TETRA-4-TERTIARY BUTYLPHTHALOCYANINE IN SHPOLSKII MATRICES
(1994-04-01)
CHEN, WH
;
GAO, J
;
RIECKHOFF, KE
;
VOIGT, EM
;
電子物理學系
We report experimental results of the ground state proton tunneling rate constant k in the absence of radiation to be from 0.03 to 0.35 s-1 at temperatures from 4.2 to 77 K for tetra-4-tertiary butylphthalocyanine tautomers embedded in hexadecane matrices. While a detailed microscopic description of the exact transfer mechanism is not possible from the data obtained so far, we present a model based on a new type of potential barrier and use the semiclassical WKB approximation to calculate transmission data compatible with experiment.