Browsing by Author "CHAO, CY"

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ANOMALOUS DOPING BEHAVIOR OF IN-SITU BORON-DOPED POLYCRYSTALLINE SILICON DEPOSITED BY ULTRAHIGH-VACUUM CHEMICAL-VAPOR-DEPOSITION
(1993-09-13)
LIN, HC
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LIN, HY
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CHANG, CY
;
LEI, TF
;
WANG, PJ
The deposition of in situ heavily boron-doped polycrystalline silicon (poly-Si) films was studied using an ultrahigh vacuum/chemical vapor deposition system. Fully activated carrier concentrations up to 3X10(20) cm-3 were obtained for the as-deposited films grown at 550-degrees-C. For boron concentration beyond this level, the crystallinity of poly-Si films degraded with increasing boron concentration, which resulted in an anomalous rise in resistivity. This crystallinity degradation occurred at a higher rate for films grown on a SiO2 surface than those grown on an undoped poly-Si surface. It is attributed to the preferential adsorption of boron atoms on the SiO2 surface. Under a high B2H6 flux condition, a large amount of boron atoms would accumulate on the SiO2 Surface before the formation of Si nuclei, and thus disturbs the subsequent film deposition and grain growth processes.
GRAIN-BOUNDARY PRECIPITATION IN AN FE-28.6MN-9.8AL-0.8SI-1.0C ALLOY
(1991-07-01)
CHAO, CY
;
LIU, TF
;
交大名義發表
;
材料科學與工程學系
;
National Chiao Tung University
GRAIN-BOUNDARY PRECIPITATION IN AN FE-7.8AL-31.7MN-0.54C ALLOY
(1993-01-01)
CHAO, CY
;
HWANG, CN
;
LIU, TF
;
交大名義發表
;
材料科學與工程學系
GRAIN-BOUNDARY PRECIPITATION IN AN FE-8.0AL-31.5MN-1.05C ALLOY
(1993-01-15)
HWANG, CN
;
CHAO, CY
;
LIU, TF
;
交大名義發表
;
材料科學與工程學系
GROWTH OF UNDOPED POLYCRYSTALLINE SI BY AN ULTRAHIGH-VACUUM CHEMICAL-VAPOR-DEPOSITION SYSTEM
(1993-09-06)
LIN, HC
;
LIN, HY
;
CHANG, CY
;
LEI, TF
;
WANG, PJ
Deposition of undoped polycrystalline-silicon (poly-Si) films on SiO2 using an ultrahigh vacuum chemical vapor deposition system was investigated. Poly-Si films with high crystallinity were obtained at a temperature as low as 525-degrees-C. The layer growth process was found to proceed with an activation energy of 44 +/- 2 kcal/mol, and is dominated by the desorption rate of surface-bonded hydrogen atoms. An incubation time was observed prior to the film deposition. This incubation period increased with decreasing growth temperature, resulting from slower nucleation and growth rates ai lower temperatures.
PHASE-TRANSFORMATION IN AN FE-9.0AL-29.5MN-1.2SI ALLOY
(1991-06-01)
LIU, TF
;
UEN, GC
;
CHAO, CY
;
LIN, YL
;
WU, CC
The microstructure of an (alpha + gamma) duplex Fe-9.0Al-29.5Mn-1.2Si alloy has been investigated by means of transmission electron microscopy. In the as-quenched condition, extremely fine D0(3) particles were formed within the ferrite matrix by a continuous ordering transition during quenching. After being aged at 550-degrees-C, the extremely fine D0(3) particles existing in the as-quenched specimen grew preferentially along [100] directions. With increasing the aging time at 550-degrees-C, a (Si, Mn)-rich phase (designated as "L phase") began to appear at the regions contiguous to the D0(3) particles. The L phase has never been observed in various Fe-Al-Mn, Fe-Al-Si, Fe-Mn-Si, and Mn-Al-Si alloy systems before. When the as-quenched specimen was aged at temperatures ranging from 550-degrees-C to 950-degrees-C, the phase transformation sequence occurring within the (alpha + D0(3)) region as the aging temperature increases was found to be (alpha + D0(3) + L phase) --> (alpha + D0(3) + A13 beta-Mn) --> (B2 + D0(3) + A13 beta-Mn) --> (B2 + A13 beta-Mn) --> (alpha + A13 beta-Mn) --> (alpha + gamma) --> alpha.
PHASE-TRANSFORMATIONS IN AN FE-7.8AL-29.5MN-1.5SI-1.05C ALLOY
(1993-09-01)
CHAO, CY
;
LIU, TF
;
機械工程學系
;
材料科學與工程學系
;
Department of Mechanical Engineering
Phase transformations in an Fe-7.8Al-29.5Mn-1.5Si-1.05C alloy have been investigated by means of optical microscopy and transmission electron microscopy. In the as-quenched condition, a high density of fine (Fe,Mn)3AlC carbides could be observed within the austenite matrix. When the as-quenched alloy was aged at temperatures ranging from 550-degrees-C to 825-degrees-C, a gamma --> coarse (Fe,Mn)3AlC carbide + DO3 reaction occurred by a cellular precipitation on the gamma/gamma grain boundaries and twin boundaries. Both of the observations are quite different from those observed by other workers in Fe-Al-Mn-C alloys. In their studies, it was found that the as-quenched microstructure was austenite phase (gamma), and (Fe,Mn)3AlC carbides could only be observed within the austenite matrix in the aged alloys. In addition, a gamma --> alpha (ferrite) + coarse (Fe,Mn)3AlC carbide reaction or a gamma --> alpha + coarse (Fe,Mn)3AlC carbide + beta-Mn reaction was found to occur on the gamma/gamma grain boundary in the aged Fe-Al-Mn-C alloys.
SPINODAL DECOMPOSITION IN FE-9.0AL-30.5MN-XC ALLOYS
(1993-09-01)
CHAO, CY
;
HWANG, LK
;
LIU, TF
;
交大名義發表
;
材料科學與工程學系
THE EFFECT OF GATE ELECTRODES USING TUNGSTEN SILICIDES AND OR POLYSILICON ON THE DIELECTRIC CHARACTERISTICS OF VERY THIN OXIDES
(1990-03-01)
CHENG, HC
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CHAO, CY
;
SU, WD
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CHANG, SW
;
LEE, MK