Browsing by Author "HSU, SE"

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ADHESION AND TRIBOLOGICAL PROPERTIES OF DIAMOND FILMS ON VARIOUS SUBSTRATES
(1990-11-01)
KUO, CT
;
YEN, TY
;
HUANG, TH
;
HSU, SE
;
機械工程學系
GROWTH AND CHARACTERIZATION OF BI12(SI1-XTIX)O20 MIXED-CRYSTALS
(1993-06-01)
YEH, TS
;
HU, LJ
;
TU, SL
;
YANG, SJ
;
HSU, SE
Crystal growth of a sillenite structure with a composition of Bi12(Si1-xTix)O20 and the corresponding optical characteristics have been systematically examined. The incongruent melting materials Bi12TiO20(BTO) have been observed to form a solid solution with congruent melting materials Bi12SiO20(BSO) for the whole range of the x value. The cutoff wavelength increases and the optical activity decreases linearly with BTO content in the crystals. The photorefractive effect is modified significantly due to the addition of BTO. The diffraction efficiency (eta) of the photorefractive grating increases first with BTO content for x less-than-or-equal-to 0.33 and saturates for a larger amount of BTO addition. The response speed is, however, promoted markedly for x greater-than-or-equal-to 0.48.
LOW-TEMPERATURE GROWTH OF DIAMOND FILMS BY MICROWAVE PLASMA CHEMICAL-VAPOR-DEPOSITION USING CH4+CO2 GAS-MIXTURES
(1994-04-01)
CHEN, CF
;
CHEN, SH
;
KO, HW
;
HSU, SE
;
材料科學與工程學系
Diamond films were deposited on Si substrates at low temperatures using CH4 + CO2 gas mixtures, which are different from conventional mixtures such as CH4 + H-2, CH4 + O2 + H-2 and CO + O2 + H-2. The films were deposited by microwave plasma chemical vapor deposition. High quality diamond films with high growth rates were fabricated at lower temperatures than those used by previous researchers. After 24 h of deposition, the deposited films were characterized using scanning electron microscopy, and their quality was determined by laser Raman spectroscopy and X-ray diffraction. The results showed that, when the microwave power was set at 290 W, well-faceted diamond films were formed in the total gas pressure range 6-25 Torr. The substrate temperatures and the volume ratios [CH4]/[CO2] (in volume per cent) were also changed from 340 to 220-degrees-C and from 60.1 % to 57.3% respectively. The growth rate of diamond films changed from 0.31 to 0.18 mum h-1 in the above growth temperature range. The growth rate of the diamond films increased as the substrate temperature increased. Consequently, we predict that diamond films may be formed using CH4 + CO2 gas mixtures, even at temperatures of less than 200-degrees-C.
OPTIMIZATION OF DEPOSITING Y1BA2CU3O7-DELTA SUPERCONDUCTING THIN-FILMS BY EXCIMER LASER ABLATION WITH CO2 LASER-HEATED SUBSTRATES
(1992-06-01)
WU, KH
;
JUANG, JY
;
LEE, CL
;
LAI, TC
;
UEN, TM
The optimum deposition conditions for growing Y1Ba2Cu3O7-delta superconducting thin films in situ by using xenon, Nd:YAG, and KrF excimer lasers with CO2 laser-heated substrates were studied. The dependences of the T(c0) and microstructure of the films on the deposition parameters such as substrate temperature, oxygen partial pressure, laser energy density and repetition rates have been investigated systematically. It was found that both the surface mobility on the substrate and the reaction temperatures for the particulates arriving at the substrates are the key factors for obtaining high-quality films. High-quality Y1Ba2Cu3O7-delta thin films with mirror-like surface morphology, T(c0) almost-equal-to 90 K, and nearly perfect c-axis oriented normal to the film surface were routinely grown in situ on SrTiO3 substrates with the following deposition conditions: substrate temperature at 670-degrees-C, oxygen partial pressure of 0.1 torr, laser energy density of 4 J/cm2 per pulse, and repetition rate of 10 Hz. More significantly, it took only about 3 min to grow a 0.3-mu-m thick film and less than 50 s to cool down the film to room temperature after deposition by the present process. Subsequent processes, such as slow cooling in oxygen atmosphere or any further heat treatments, were unnecessary for the present process. The unique advantage of the present process further offered us good opportunities to delineate the effects of each deposition parameter on the detailed film growth mechanisms without having to deal with the complications introduced by prolonged post-deposition treatments. The details of all the interesting features observed will be presented and their physical implications will be discussed.