Browsing by Author "CHANG, PH"

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Al2O3 films formed by anodic oxidation of Al-1wt.%Si-0.5wt%Cu films
(1994)
CHIU, S
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CHANG, PH
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TUNG, CH
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材料科學與工程學系
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Department of Materials Science and Engineering
AL2O3 FILMS FORMED BY ANODIC-OXIDATION OF AL-1 WEIGHT PERCENT SI-0.5 WEIGHT PERCENT CU FILMS
(1995-02-01)
CHIU, RL
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CHANG, PH
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TUNG, CH
;
材料科學與工程學系
;
Department of Materials Science and Engineering
The structure of the barrier-type anodic oxide formed on preannealed Al-1 weight percent (w/o) Si-0.5 w/o Cu thin film in a tartaric acid electrolyte was investigated. The oxide film is basically an amorphous layer with a thin dispersed gamma'-Al2O3 crystalline layer interposed in the center. Pores are observed to be associated with the gamma'-Al2O3 layer. Silicon nodules and Al2Cu particles originally present in the Al-1 w/o Si-0.5 w/o Cu film behave differently during anodization. Silicon nodules are oxidized to various degree during anodizing. The silica formed in the Si nodules is amorphous and somewhat porous possibly due to oxygen evolution associated with the Si anodization. A dark rim was found to surround each nodule in the anodic oxide film. This rim is shown to be thicker amorphous Al2O3 material, and its origin is attributed to the faster oxidation rate in the vicinity of Si nodules. Al2Cu precipitates are oxidized to form Al2O3 at about the same rate as the surrounding Al matrix. Copper is rejected by Al2O3 and accumulates at the Al2O3/Al interface.
BARRIER EFFECT OF E-BEAM EVAPORATED TUNGSTEN INTERLAYER IN AL/W/PTSI METALLIZATION LAYER
(1988-09-01)
CHIOU, BS
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LO, HS
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CHANG, PH
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電控工程研究所
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Institute of Electrical and Control Engineering
CHARACTERISTICS OF TITANIUM SILICIDE FORMED BY SI/MO/TI TRILAYER METALLIZATION
(1989-03-01)
CHIOU, BS
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YANG, BJ
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CHANG, PH
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交大名義發表
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電子物理學系
EQUIVALENT-CIRCUIT MODEL IN GRAIN-BOUNDARY BARRIER LAYER CAPACITORS
(1989-10-01)
CHIOU, BS
;
LIN, ST
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DUH, JG
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CHANG, PH
;
電控工程研究所
INTERACTIONS BETWEEN AL-1 WT-PERCENT SI THIN-FILM AND W-TI BARRIER LAYER
(1994-05-15)
CHANG, PH
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CHEN, HM
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LIU, HY
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BOHLMAN, JG
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材料科學與工程學系
The interaction of Al-1 wt% Si with a W-Ti barrier layer in the Al/Ti3W7/SiO2/Si system was studied over the temperature range of 400-500-degrees-C for reaction times up to 300 h. The interaction was found to be diffusion-controlled, and to occur in a layer-by-layer fashion. The first reaction product is always Al12W, which forms at the Al/Ti3W7 interface. With excess W in the system, Al will eventually be completely converted to Al12W, and further interactions result in the formation of an Al4W layer at the Al12W/Ti3W7 interface. The amount of Al4W increases at the expense of Al12W. Ti plays a minor role in the interaction and forms a small amount of Al3Ti precipitates in the Al12W matrix. Decomposition of the Ti3W7 pseudoalloy into W and Ti phases is not significant, and is not detected by X-ray diffraction even after annealing at 500-degrees-C for 300 h. The kinetics of the Al12W formation follows a parabolic reaction law with an activation energy of 2.53 eV. The sheet resistance of the film is insensitive to compound formation as long as a continuous Al film exists in the system. The sheet resistance increases dramatically when Al is consumed to the extent that it is no longer a continuous film. The sheet resistance of the Al12W layer is estimated to be 570 mOMEGA square-1.
MICROSTRUCTURE AND PROPERTIES OF MULTILAYER-DERIVED TUNGSTEN SILICIDE
(1987-07-01)
CHIOU, BS
;
RAU, HL
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CHANG, PH
;
DUH, JG
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電控工程研究所
STRUCTURES OF TANTALUM PENTOXIDE THIN-FILMS FORMED BY REACTIVE SPUTTERING OF TA METAL
(1995-03-15)
CHANG, PH
;
LIU, HY
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材料科學與工程學系
;
Department of Materials Science and Engineering
Reactively sputtered Ta2O5 films adhere poorly on bare Si substrate, but the adhesion improves dramatically on a thermally oxidized Si surface. The films are non-stoichiometric and the atomic ratio of O to Ta is typically higher than 2.5 but decreases with increasing annealing temperature. The variation in non-stoichiometry is also reflected by a small decrease in lattice constants with increasing annealing temperature as revealed by X-ray diffraction. About 2at% of residual Ar is detected in Ta2O5 film formed by 70%Ar-30%O-2 sputtering. The as-deposited Ta2O5 film is amorphous and it transforms to crystalline Ta2O5 at temperatures higher than 600 degrees C. Crystalline Ta2O5 films contain numerous amorphous particles which have been previously incorrectly identified as voids. They are probably the remnants of the uncrystallized amorphous Ta2O5 materials. The amorphous particles have a bimodal size distribution and the average size increases with increasing annealing temperature. The deterioration of dielectric properties in crystallized Ta2O5 films is unlikely to arise from these amorphous particles because amorphous Ta2O5 is known to have very low leakage current. An interfacial SiO2 layer forms at the Ta2O5-Si interface during reactive sputtering and its thickness increases with increasing oxygen content in the sputtering gas. Annealing at high temperature in Ar ambient has little effect on the thickness of this interfacial SiO2 layer.
THE EFFECT OF ANODIZING TEMPERATURE ON ANODIC OXIDE FORMED ON PURE AL THIN-FILMS
(1995-05-01)
CHIU, RL
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CHANG, PH
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TUNG, CH
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材料科學與工程學系
;
Department of Materials Science and Engineering
The structure and properties of anodic Al2O3 films formed at different anodizing temperatures from thin Al films deposited by magnetron sputtering on oxidized Si wafers have been studied by transmission electron microscopy, secondary ion mass spectrometry, and electrical measurements. The anodic oxide films formed at 8 degrees C and 25 degrees C are amorphous with excellent dielectic properties, leakage current lower than 500 nA at 7.5 MV cm(-1) and no breakdown up to 7.5 MV cm(-1). Partially crystalline gamma'-Al2O3 is grown at the upper half of the 58 degrees C oxide film. This film exhibits much inferior dielectric properties than the lower temperature films. Carbon is incorporated into the top portion of the oxide films from the electrolyte during anodizing and it has little effect on the crystalline oxide formation. Oxygen penetrates into the underlying Al layer during anodizing. The penetration increases with increasing anodizing temperature.
THE EFFECT OF SI AND CU ON THE INTERACTIONS BETWEEN AL FILMS AND A TIW BARRIER LAYER
(1992-10-01)
CHANG, PH
;
CHEN, HM
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LIU, HY
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材料科學與工程學系
;
Department of Materials Science and Engineering
The effect of doping 1 wt % Si or 0.9 wt % Cu to Al films on the interactions between Al and TiW barrier layers at 450-degrees-C was studied. It was found that the first product is always Al12W, which forms at the Al/TiW interface, irrespective of the dopant addition. However, doping 1 wt % Si to Al film enhances the Al12W formation while doping 0.9 wt % Cu retards its formation. With excess tungsten in the system, Al12W would further react with W to form Al/W compounds with higher W content. In pure Al film, both the hexagonal Al5W phase and the monoclinic Al4W phase were detected to form after prolonged annealing at 450-degrees-C. The addition of 1 wt % Si or 0.9 wt % Cu to Al prohibits the formation of Al5W, thus only the Al4W phase was observed at the W/Al12W interface in the doped Al films.