Browsing by Author "Wu, YH"

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Characteristics of fluorinated amorphous carbon films and implementation of 0.15 mu m Cu/a-C : F damascene interconnection
(2001-05-01)
Shieh, JM
;
Suen, SC
;
Tsai, KC
;
Dai, BT
;
Wu, YC
Fluorinated amorphous carbon films (a-C:F) deposited by plasma enhanced chemical vapor deposition with low dielectric constant (K similar to2.3), thermal stability (higher than 400 degreesC) and acceptable adhesion to a cap layer such as SiOF or SiO2 were obtained by varying the range of content ratios between carbon and fluorine, the rf power, the process pressure and the base temperature. Standard x-ray photoelectron spectroscopy and thermal desorption spectroscopy metrologies were employed to characterize the deposited a-C:F films. The damascene pattern with 0.15 mum and an etching selectivity of more than 50 (a-C:F/SiOF, SiO2) was implemented by a mixture of etching gases of N-2+O-2. The bias power, rf power and gas hows were incorporated to optimize the etching recipe for achieving a damascene profile with a high aspect ratio. The scanning electron microscope results showed that a better etch profile can be obtained at higher bias power. In our damascene architecture, the etching stop layer or hard mask of both SiOF and SiO2 was studied. The SiOF, providing a lower dielectric constant than SiO2, would especially reduce the entire effective dielectric constant. Furthermore, we integrated electroplated copper into trenches or vias as small as 0.15 mum, with aspect ratio of 6. (C) 2001 American Vacuum Society.
Electrical characteristics of high quality La2O3 gate dielectric with equivalent oxide thickness of 5 angstrom
(2000-07-01)
Wu, YH
;
Yang, MY
;
Chin, A
;
Chen, WJ
;
Kwei, CM
Electrical and reliability properties of ultrathin La2O3 gate dielectric have been investigated. The measured capacitance of 33 Angstrom La2O3 gate dielectric is 7.2 mu F/cm(2) that gives an effective K value of 27 and an equivalent oxide thickness of 4.8 Angstrom. Good dielectric integrity is evidence from the low leakage current density of 0.06 A/cm(2) at -1 V, high effective breakdown field of 13.5 MV/cm, low interface-trap density of 3 x 10(10) eV-1/cm(2), and excellent reliability with more than 10 years lifetime even at 2 V bias. In addition to high K, these dielectric properties are very close to conventional thermal SiO2.
Fabrication of very high resistivity Si with low loss and cross talk
(2000-09-01)
Wu, YH
;
Chin, A
;
Shih, KH
;
Wu, CC
;
Liao, CP
We have used proton and As+ implantation to increase the resistivity of conventional Si (10 Omega-cm) and Si-on-quartz substrates, respectively. High resistivity of 1.6 M Omega-cm is measured that is close to intrinsic Si and semi-insulating GaAs, Very low loss and cross coupling of 6.3 dB/cm and -79 dB/cm (10 mu m gap) at 20 GHz are measured on these samples, respectively. The very high resistivity and improved rf performance are due to the extremely fast similar to 1 ps carrier lifetime stable even after a 400 degrees C annealing for 1 h, Little negative effect on gate oxide integrity is also observed as evidenced by the comparable stress-induced leakage current and charge-to-breakdown for 30 Angstrom oxides.
Gate oxide integrity of thermal oxide grown on high temperature formed Si0.3Ge0.7
(2000-03-01)
Wu, YH
;
Chin, A
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
We have investigated the gate oxide integrity of thermal oxides direct grown on high temperature formed Si0.3Ge0.7 Good oxide integrity is evidenced by the low interface-trap density of 5.9 x 10(10) eV(-1)cm(-2), low oxide charge density of -5.6 x 10(10) cm(-2), and the small stress-induced leakage current after -3.3 V stress for 10 000 s, The good gate oxide integrity is due to the high temperature formed and strain-relaxed Si0.3Ge0.7 that has a original smooth surface and stable after subsequent high temperature process.
High quality La2O3 and Al2O3 gate dielectrics with equivalent oxide thickness 5-10 angstrom
(2000)
Chin, A
;
Wu, YH
;
Chen, SB
;
Liao, CC
;
Chen, WJ
High quality La2O3 and Al2O3 are fabricated with EOT of 4.8 and 9.6 Angstrom, leakage current of 0.06 and 0.4A/cm(2) and D-it of both 3x10(10) eV(-1)/cm(2), respectively. The high K is further evidenced from high MOSFET's I-d and g(m) with low I-off Good SILC and Q(BD) are obtained and comparable with. SiO2. The low EOT is due to the high thermodynamic stability in contact with Si and stable after H-2 annealing up to 550 degrees C.
High temperature formed SiGeP-MOSFET's with good device characteristics
(2000-07-01)
Wu, YH
;
Chin, A
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
We have used a simple process to fabricate Si0.3Ge0.7/Si p-MOSFET's. The Si0.3Ge0.7 is formed using deposited Ge followed by 950 degrees C rapid thermal annealing and solid phase epitaxy that is process compatible with existing VLSI. Hole mobility of 250 cm(2)/Vs is obtained from Si0.3Ge0.7 p-MOSFET that is similar to two times higher than Si control devices and results in a consequent substantially higher current drive. The 228 Angstrom Si0.3Ge0.7 thermal oxide grown at 1000 degrees C has a high breakdown field of 15 MV/cm, low interface trap density (D-it) of 1.5 x 10(11) eV(-1) cm(-2), and low oxide charge of 7.2 x 10(10) cm(-2). The source-drain junction leakage after implantation and 950 degrees C RTA is also comparable with Si counterpart.
High-quality thermal oxide grown on high-temperature-formed SiGe
(2000-05-01)
Wu, YH
;
Chen, SB
;
Chin, A
;
Chen, WJ
;
電子工程學系及電子研究所
We have developed a high-quality gate oxide on Si0.6Ge0.4 with a 30 Angstrom Si top layer. The good oxide integrity comparable to conventional thermal oxide is demonstrated by the low interface trap density of 6.2 X 10(10) eV(-1) cm(-2), low bride charge of 5.8 X 10(10) cm(-2), small leakage current at 3.3 V of 4.2 x 10(-8) A/cm(2), high breakdown field of 13.8 MV/cm, good charge-to-breakdown of 5.2 C/cm(2), and small stress-induced leakage current. This good oxide integrity is directly related to our previously developed SiGe formed by solid phase epitaxy at high temperatures that is stable during thermal oxidation. This simple process is fully compatible with existing very large scale integration technology. (C) 2000 The Electrochemical Society. S0013-4651(99)10-038-7. All rights reserved.
Hydrogen and oxygen plasma effects on polycrystalline silicon thin films of various thicknesses
(1997-06-01)
Liou, BW
;
Lee, CL
;
Lei, TF
;
Wu, YH
;
電子工程學系及電子研究所
This work studied the hydrogen and oxygen plasma effects on the resistivity, effective free carrier concentration, and mobility of As+- and BF2+-doped polycrystalline silicon (polysilicon) thin films of various thicknesses. It was found that the resistivity of a polysilicon thin film increased with the decrease of the thickness of the film. This was mainly due to the decrease of effective carrier concentration and the mobility through the decrease of the grain size since the thickness limited regrowth of the film. The hydrogen and/or oxygen plasma treatment decreased the effective carrier concentration of the film through the neutralization of boron and arsenic ions. This effect was more evident for the thinner (< 60 nm) film. The plasma treatment also decreased the mobility of the film, unless the thickness of the film was thinner than 50 nm, for which, the mobility instead increased since the plasma passivation effect became dominant.
Improved electrical characteristics of CoSi2 using HF-vapor pretreatment
(1999-05-01)
Wu, YH
;
Chen, WJ
;
Chang, SL
;
Chin, A
;
Gwo, S
We have developed a simple process to form epitaxial CoSi2 for shallow junction. Prior to metal deposition, the patterned wafers were treated with HF-vapor passivation. As observed by scanning tunneling microscopy (STM), this HF, treatment drastically improves the native oxide-induced sur face roughness. The epitaxial behavior was confirmed by cross-sectional transmission electron microscopy (TEM), Decreased sheet resistance and leakage current, and improved thermal stability are displayed by the HF treated samples, which is consistent with STM and TEM results.
Improved electrical characteristics of CoSi2 using HF-vapor pretreatment
(1999-05-01)
Wu, YH
;
Chen, WJ
;
Chang, SL
;
Chin, A
;
Gwo, S
We have developed a simple process to form epitaxial CoSi2 for shallow junction. Prior to metal deposition, the patterned wafers were treated with HF-vapor passivation. As observed by scanning tunneling microscopy (STM), this HF, treatment drastically improves the native oxide-induced sur face roughness. The epitaxial behavior was confirmed by cross-sectional transmission electron microscopy (TEM), Decreased sheet resistance and leakage current, and improved thermal stability are displayed by the HF treated samples, which is consistent with STM and TEM results.
Improved electrical characteristics of CoSi2 using HF-vapor pretreatment
(1999-07-01)
Wu, YH
;
Chen, WJ
;
Chang, SL
;
Chin, A
;
Gwo, S
We have developed a simple process to form epitaxial CoSi2 for shallow junction. Prior to metal deposition, the patterned wafers were treated with HF-vapor passivation. As observed hy scanning tunneling microscopy (STM), this HF treatment drastically improves the native oxide-induced surface roughness. The epitaxial behavior was confirmed by cross-sectional transmission electron microscopy (TEM). Decreased sheet resistance and leakage current, and improved thermal stability are displayed by the HF treated samples, which is consistent with STM and TEM results.
Optoelectronic characteristics of a-SiC : H-based pin thin film LEDs having a thin Mo buffer layer in contact with p-type a-Si : H
(1998-07-09)
Chen, YA
;
Wu, YH
;
Tsay, WC
;
Laih, LH
;
Hong, JW
To improve the electroluminescence (EL) properties of the nSiC:H-based pin thin film light-emitting diodes (TFLEDs) with the promotion of hole injection efficiency, a thin Mo metal film was used as a buffer layer to prevent reactions between the ITO (indium-tin-oxide) electrode and the p(+)-a-Si:H layer. With the formation of semi-transparent Mo silicide after annealing, a lower EL threshold voltage and a significantly higher brightness for a finished TFLED were achieved. The brightness of the obtained device was 1300cd/m(2) at an injection current density of 600mA/cm(2), and its EL threshold voltage was 14V.
Reduction of etching plasma damage on low dielectric constant fluorinated amorphous carbon films by multiple H-2 plasma treatment
(2002-07-01)
Shieh, JM
;
Tsai, KC
;
Dai, BT
;
Wu, YC
;
Wu, YH
Two-step hydrogen plasma treatment on low dielectric constant (low-k) fluorinated amorphous carbon films (a-C:F) was conducted to improve their thermal stability and reduce the damage caused by the patterning processes. First, hydrogen plasma treatment repairs imperfect bonds of as-deposited a-C:F films, stabilizing their chemical structures and increasing their resistance against elevated thermal stresses. After this passivation process, an additional hydrogen plasma treatment was applied to a-C:F films that had been etched using a mixture of N-2+O-2+CHF3, enabling sub-130 nm damascene trenches to be patterned and repairing the chemical structures destroyed by the etching plasma. (C) 2002 American Vacuum Society.
Rf loss and cross talk on extremely high resistivity (10K-1M Omega-cm) Si fabricated by ion implantation
(2000)
Wu, YH
;
Chin, A
;
Shih, KH
;
Wu, CC
;
Liao, CP
We have achieved 1.6M Omega -cm resistivity using ion implantation that has little negative effect on MOS devices. Extremely low loss and cross coupling of 6.3 and -79 dB/cm (10 mum gap) at 20GHz are measured with 1 mum Al, respectively, which is due to implant induced trap with similar to 1ps carrier lifetime and stable to 400 degreesC.
The buried oxide properties in oxygen plasma-enhanced low-temperature wafer bonding
(2000-07-01)
Wu, YH
;
Huang, CH
;
Chen, WJ
;
Lin, CN
;
Chin, A
We have studied the buried oxide integrity in oxygen plasma-enhanced low-temperature wafer bonding. As observed by cross-sectional scanning electron microscopy, the bonding strength of the oxygen plasma-treated sample is so large that forced separation for a 600 degrees C bonded wafer takes place at the heterointerface of the thermal oxide and the Si substrate rather than at the oxide-oxide bonding interface. The plasma-enhanced bonding shows good structure property with negligible defects as observed by cross-sectional transmission electron microscopy. From capacitance-voltage measurement, good electrical property is evidenced by the low oxide-charge and interface-trap densities of -2.0 x 10(10) cm(-2) and 3 x 10(10) eV(-1) cm(-2), respectively, from capacitance-voltage measurements. (C) 2000 The Electrochemical Society. S0013-4651(99)11-083-8. All rights reserved.
The effect of copper on gate oxide integrity
(2000-11-01)
Lin, YH
;
Wu, YH
;
Chin, A
;
Pan, FM
;
電子工程學系及電子研究所
We have studied the effect of copper contamination after the front-end metal-oxide-semiconductor capacitor fabrication on gate oxide integrity. The significant effect of Cu contamination on the pretunneling current, in combination with insensitive dependence of the Fowler-Nordheim tunneling current, oxide charge density, and breakdown field on the Cu concentration, suggests that the current leakage mechanism may be due to neutral traps generated by Cu inside oxide. In addition to pretunneling oxide leakage, a small amount of Cu contamination increases the interface trap density that may degrade the device performance. (C) 2000 The Electrochemical Society. S0013-4651(00)03-073-1. All rights reserved.
The effect of native oxide on epitaxial SiGe from deposited amorphous Ge on Si
(1999-01-25)
Wu, YH
;
Chen, WJ
;
Chin, A
;
Tsai, C
;
電子工程學系及電子研究所
We have investigated the effect of native oxide on the epitaxial SiGe from deposited amorphous Ge on Si. Instead of epitaxial growth by molecular beam epitaxy or ultrahigh-vacuum chemical vapor deposition, the SiGe layer is formed by this simple process followed by an annealing step. As observed by transmission electron microscopy, the suppression of native oxide plays an important role to achieve epitaxial SiGe. The SiGe quality degrades with increasing native oxide thickness and becomes polycrystalline with a similar to 20 Angstrom interfacial native oxide. On the other hand, single crystalline SiGe can be routinely formed from a HF-vapor treated Si surface. (C) 1999 American Institute of Physics. [S0003-6951(99)04504-0].
The market size of a city-pair route at an airport
(1997-09-01)
Hsu, CI
;
Wu, YH
;
交大名義發表
;
運輸與物流管理系註：原交通所+運管所
;
National Chiao Tung University
A model is developed for estimating the size of the market for a city-pair route at an airport from both the demand and supply sides of air transportation. The average airport access cost, average passenger delay cost, and average airline operating cost all either increase or decrease with an increase in the market size of a city-pair route at an airport, so the optimum market size can be determined from trade-offs among these costs. A nonlinear mathematical programming problem is formulated to determine the optimal number of passengers, the local service area of a city-pair market and to perform sensitivity analyses. The results show that long-haul services ought to be concentrated in one large airport, while short-haul services might be dispersed among many small airports. Improvements in the technology of the airport access mode or increases in the average income of the cities served can expand the market size and service area, but at a declining expansion rate. In metropolitan areas with high population density, airlines can operate more efficiently and distribute air services among more airports. City-pair markets with stable passenger demand, or markets served by airlines with efficient scheduling technology are shown to exhibit high cost efficiencies.
The performance limiting factors as RF MOSFETs scaling down
(2000)
Wu, YH
;
Chin, A
;
Liang, CS
;
Wu, CC
;
電子工程學系及電子研究所
The measured RF performance of 0.5, 0.25, and 0.18 mum MOSFETs gradually saturates as scaling down, which can be explained by the derived analytical equation and simulation. The overlap C-gd and non-quasi-static effect are the main factors but scales much slower than L-g.
Thickness dependent gate oxide quality of thin thermal oxide grown on high temperature formed SiGe
(2000-06-01)
Wu, YH
;
Chin, A
;
Chen, WJ
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
For thin oxides grown on high temperature formed Si0.3Ge0.7, the gate oxide quality is strongly dependent on oxide thickness and improves as thickness reduces from 50 to 30 Angstrom. The thinner 30 Angstrom oxide has excellent quality as evidenced by the comparable leakage current, breakdown voltage, interface-trap density and charge-to-breakdown with conventional thermal oxide grown on Si. The achieved good oxide quality is due to the high temperature formed Si0.3Ge0.7 that is strain relaxed and stable during oxidation, The possible reason for strong thickness dependence may be due to the lower GeO2 content formed in thinner 30 Angstrom oxide rather than strain relaxation related rough surface or defects.