Browsing by Author "Chiang, CC"

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Barrier characteristics of PECVD alpha-SiC : H dielectrics
(2001)
Chiang, CC
;
Wu, ZC
;
Wu, WH
;
Chen, MC
;
Ko, CC
This work investigates the thermal stability and barrier characteristics of three species of PECVD alpha-SiC:H dielectric films with dielectric constants between 3.5 and 5.4. It is found that the dielectric constant decreases with increasing content of carbon in the alpha-SiC:H film. All of the three specie's of alpha-SiC:H films are thermally stable at temperatures of up to 500degreesC. However, degraded barrier capability and moisture resistance were observed for the alpha-SiC:H film with a k value around 3.5, which has a C/Si atomic ratio of 0.875. This is presumably attributed to poorly crosslinked molecular structure and porosity enhancement by the abundant amount of carbon in the alpha-SiC:H film.
Co-DRR: An integrated uplink and downlink scheduler for bandwidth management over wireless LANs
(2003)
Wei, HY
;
Chiang, CC
;
Lin, YD
;
資訊工程學系
;
Department of Computer Science
Bandwidth management over wired bottleneck links has been an effective way to utilize network resources. For the rapidly emerging IEEE 802.11 Wireless LAN (WLAN), the limited WLAN bandwidth becomes a new bottleneck and requires bandwidth management. Most possible existing solutions only exclusively focus on optimizing multimedia traffic, pure downlink or pure uplink fairness, or are incompatible with IEEE 802.11. This study proposes a cooperative deficit round robin (co-DRR), an IEEE 802.11-compatible host-based fair scheduling algorithm based on the deficit round robin (DRR) and distributed-DRR (DDRR) schemes, to cooperate the uplink and downlink quantum calculations to simultaneously control uplink and downlink bandwidth. Co-DRR uses the standard PCF mode to utilize the contention-free period to compensate for the unfairness in the contention period. Numerical results demonstrate that: co-DRR can scale up to 100 mobile hosts even under high bit error rate (0.0001) while simultaneous achieving uplink/downlink long-term fairness (CoV<0.01) among competing mobile hosts.
Comparative study of physical and electrical characteristics of F- and C-doped low-K CVD oxides
(2001)
Wu, ZC
;
Shiung, ZW
;
Chiang, CC
;
Wu, WH
;
Chen, MC
This work makes a comparative study of physical and electrical properties between two species of inorganic low-K CVD oxides, namely F-doped FSG (fluorinated silicate glass, K=3.5) and C-doped OSG (organosilicate glass, K=2.9). It is found that FSG has a higher thermal stability (>600degreesC) than OSG (500degreesC) based on the results of 30 min thermal anneal in N-2 ambient. The degradation of the low-K property in OSG is predominately due to the thermal decomposition of methyl (CH3) groups at temperatures above 500degreesC, which are incorporated to reduce the density and polarizability of OSG. For the Cu-gated oxide-sandwiched low-K dielectric MIS capacitors, Cu permeation was observed in both FSG and OSG after the MIS capacitors were subjected to bias-temperature stressing (BTS) at 250 and 150degreesC, respectively, with an effective applied field of 0.8 MV/cm. It appeared that Cu drifted more readily in OSG than in FSG presumably because OSG has a more porous and less dense structure than FSG. The Cu penetration can be efficiently mitigated by a thin nitride dielectric barrier layer.
Divide-and-conquer learning and modular perceptron networks
(2001-03-01)
Fu, HC
;
Lee, YP
;
Chiang, CC
;
Pao, HT
;
資訊工程學系
A novel modular perceptron network (MPN) and divide-and-conquer learning (DCL) schemes for the design of modular neural networks are proposed, When a training process in a multilayer perceptron fails into a local minimum or stalls in a flat region, the proposed DCL scheme is applied to divide the current training data region (e.g,, a hard to be learned training set) into two easier (hopely) to be learned regions. The learning process continues when a self-growing perceptron network and its initial weight estimation are constructed for one of the newly partitioned regions, Another partitioned region will resume the training process on the original perceptron network. Data region partitioning, weight estimating and learning are iteratively repeated until all the training data are completely learned by the MPN We have evaluated and compared the proposed MPN with several representative neural networks on the two-spirals problem and real-world dataset, The MPN achieves better weight learning performance by requiring much less data presentations (99.01% similar to 87.86% lesser) during the network training phases, and better generalization performance (4.0% better), and less processing time (2.0% similar to 81.3% lesser) during the retrieving phase, On learning the real-world data, the MPN's show less overfitting compared to single MLP. In addition, due to its self-growing and fast local learning characteristics, the modular network (MPN) can easily adapt to on-line and/or incremental Learning requirements for a rapid changing environment.
Effects of O-2- and N-2-plasma treatments on copper surface
(2004-11-01)
Chiang, CC
;
Chen, MC
;
Li, LJ
;
Wu, ZC
;
Jang, SM
In this work, we investigate the effects of oxygen (O-2) and nitrogen (N-2) plasma treatments on the copper surface of aluminum/amorphous silicon-nitricarbide/copper (Al/alpha-SiCN/Cu) metal-insulator-metal (MIM) capacitors with respect to their leakage current and breakdown field. It is found that both the O-2- and N-2-plasma treatments have an adverse effect on the leakage current and breakdown field of MIM capacitors. The MIM capacitors with their Cu surfaces subjected to O-2- or N-2-plasma treatment exhibit a room-temperature leakage current density several orders of magnitude larger than that of the sample without plasma treatment at the same applied electric field. The room-temperature breakdown fields of the MIM capacitors with O-2- and N-2-plasma-treated Cu surfaces are 3.8 and 3.2 MV/cm, respectively, while that of the control sample without plasma treatment is 7.8MV/cm. The increased leakage currents and degraded breakdown fields of the O-2- and N-2-plasma-treated samples are attributed, respectively, to the presence of metastable Cu-O oxide and Cu-N azide at the Cu surfaces.
Four-dimensional dielectric property image obtained from electron spectroscopic imaging series
(2001)
Lo, SC
;
Kai, JJ
;
Chen, FR
;
Chang, L
;
Chen, LC
We have demonstrated a new quantitative method to characterize two- dimensional distributions of energy-dependent dielectric function of materials from low loss electron spectroscopic image (ESI) series. Two problems associated with extracted image-spectrum from the low-loss image series, under-sampling and loss of energy resolution, were overcome by using fast Fourier transformation (FFT) interpolation and maximum entropy deconvolution method. in this study, Black Diamond(TM)/Si3N4/SiO2/Si-substrate dielectric layer designed for copper metallization was used as the sample. We show that the reconstructed (FFT interpolated and maximum entropy deconvoluted) image-spectrum obtained from ESI series images can be quantified with the same accuracy as conventional electron energy-loss spectroscopy spectra. Since the analysis of the dielectric function is sensitive to the local thickness of the specimen using Kramers-Kronig analysis, we also developed a new method to quantitatively determine the dielectric constant for low-k materials. We have determined the thickness of the Black Diamond using the extrapolated thickness method from the materials of known dielectric constants. Using Kramers-Kronig formula, the dielectric function map can be deduced front two-dimensional reconstructed single scattering spectra with providing the information of thickness. We proposed a four-dimensional data presentation for revealing the uniformity of the energy dependent property. The accuracy of our methods depends on the thickness determination and on the quality of the reconstructed spectra from the image series.
Improvement in leakage current and breakdown field of Cu-comb capacitor using a silicon oxycarbide dielectric barrier
(2004)
Chiang, CC
;
Ko, IH
;
Chen, MC
;
Wu, ZC
;
Lu, YC
This work investigates in the first place, the improvement in leakage current and breakdown field of the copper metal-insulator-semiconductor (Cu-MIS) capacitor with a plasma-enhanced chemical vapor deposited (PECVD) amorphous silicon oxycarbide (alpha-SiCO, k = 3.7) dielectric barrier. This is followed by investigating the improvement in leakage current and breakdown field of the Cu-comb capacitor with a carbon-doped low-k PECVD organosilicate glass (k = 3) as the intermetal dielectric and an alpha-SiCO dielectric film as the Cu cap barrier. The leakage current and breakdown field of Cu-MIS and Cu-comb capacitors are dependent on the species of the dielectric barrier. The Cu-MIS and Cu-comb capacitors with an alpha-SiCO dielectric barrier exhibit a leakage current at least three orders of magnitude smaller than those with an amorphous silicon carbide (alpha-SiC, k = 4.4) dielectric barrier at an applied electric field of 1.6 MV/cm between 25 and 250 degreesC. Moreover, the breakdown field of the Cu-MIS and Cu-comb capacitors with an alpha-SiCO dielectric barrier, measured at 200 degreesC, are 60 and 25%, respectively, higher than that of the capacitors with an alpha-SiC barrier. The decreased leakage current and increased breakdown field of the Cu-MIS and Cu-comb capacitors with an alpha-SiCO dielectric barrier are attributed to the higher density, oxygen-improved film property, nonsemiconductor behavior, and lower fringe- or surface-electric field of the alpha-SiCO dielectric film. (C) 2004 The Electrochemical Society.
Leakage and breakdown mechanisms in cu damascene with a bilayer-structured a-SiCN/a-SiC dielectric barrier
(2003)
Chiang, CC
;
Ko, IH
;
Chen, MC
;
Wu, ZC
;
Lu, YC
This work investigates the leakage and breakdown mechanisms in the Cu damascene structure with a carbon-doped low-k PECVD organosilicate glass (OSG, k=3) as the intermetal dielectric (IMD) and an alpha-SiCN(k=5)/alpha-SiC(k=4) bilayer-structured dielectric film as the Cu-cap barrier. It is found that the leakage mechanism between Cu lines is dependent on the thickness ratio of the alpha-SiCN/alpha-SiC bilayer barrier in the Cu damascene structure. In the Cu damascene using an alpha-SiCN/alpha-SiC bilayer barrier of 40nm/10nm or 30nm/20nm bilayer thickness, the large leakage current (Frenkel-Poole emission) between Cu lines is attributed to the plenty of interfacial defects, such as cracks, voids, traps or dangling bonds at the alpha-SiC/OSG interface, which are generated by the larger tensile force of the thicker alpha-SiC film. On the other hand, the breakdown field and TDDB (time-dependent-dielectric-breakdown) lifetime of the Cu damascene reveal little dependence on the thickness ratio of the alpha-SiCN/alpha-SiC bilayer barrier, and the observed breakdown of the Cu damascene structure is presumably due to dielectric breakdown of the bulk OSG layer.
Leakage and breakdown mechanisms of Cu comb capacitors with bilayer-structured alpha-SiCN/alpha-SiC Cu-cap barriers
(2004-02-01)
Chiang, CC
;
Ko, IH
;
Chen, MC
;
Wu, ZC
;
Lu, YC
This work investigates the leakage and breakdown mechanisms in copper (Cu) comb capacitors with carbon-doped low-k plasma-enhanced chemical vapor deposited organosilicate glass (OSG; k = 3) as the intermetal dielectric and an alpha-SiCN (k = 5)/ alpha-SiC (k = 4) bilayer-structured dielectric film as the Cu-cap barrier. The leakage mechanism between Cu lines is dependent on the thickness ratio of the alpha-SiCN/alpha-SiC bilayer barrier. Using an alpha-SiCN/alpha-SiC bilayer barrier of 40 nm/10 nm or 30 nm/20 nm bilayer thickness, the increased leakage current (Frenkel-Poole emission) between Cu lines is attributed to the large number of interfacial defects, such as cracks, voids, traps or dangling bonds at the alpha-SiC/OSG interface, which are generated by the larger tensile force of the thicker alpha-SiC film. The Cu comb capacitor with an alpha-SiCN (50 nm)/alpha-SiC (2 nm) bilayer barrier exhibits a much smaller leakage current. The breakdown field and time-dependent dielectric breakdown lifetime of the Cu comb capacitor reveal little dependence on the thickness ratio of the alpha-SiCN/alpha-SiC bilayer barrier, and the observed breakdown of the Cu comb capacitor is presumably due to dielectric breakdown of the bulk OSG layer. (C) 2004 The Electrochemical Society.
Leakage mechanism in Cu damascene structure with methylsilane-doped low-K CVD oxide as intermetal dielectric
(2001-06-01)
Wu, ZC
;
Chiang, CC
;
Wu, WH
;
Chen, MC
;
Jeng, SM
This letter investigates the leakage mechanism in the Cu damascene structure with methylsilane-doped low-k CVD organosilicate glass (OSG) as the intermetal dielectric (IMD), The leakage between Cu lines was found to be dominated by the Frenkel-Poole (F-P) emission in OSG for the structure using a 50-nm SiC etching stop layer (ESL), In the structure using a 50-nm SiN ESL, the leakage component through SiN also made a considerable contribution to the total leakage in addition to the bulk leakage from trapped electrons in OSG, An appropriate ESL of sufficient thickness is essential to reduce the leakage through the ESL if an ESL is used in the Cu damascene integration scheme.
Market competition and programming diversity: A study on the TV market in Taiwan
(2001)
Li, SCS
;
Chiang, CC
;
傳播研究所
;
Institute of Communication Studies
This article investigates the issue of the relation between market competition and programming diversity in Taiwan's TV market. For more than 20 years, Taiwan's TV market had an oligopolistic structure with 3 networks dominating the market. With the popularity of satellite TV during the 1990s, the oligopoly rapidly ended. This study examines how programming diversity was affected by the changing TV market structure in Taiwan. Programming diversity was measured by 3 methods using program data from the 3 networks operating in Taiwan: vertical programming diversity, horizontal programming diversity, and prime-time programming strategies. The results indicate a negative relation between market competition and programming diversity. Although the market competition increased from 1986 to 1996, this study discovered that the degree of programming diversity was reduced year by year.
Oxidation of Ta diffusion barrier layer for Cu metallization in thermal annealing
(2001-06-01)
Yin, KM
;
Chang, L
;
Chen, FR
;
Kai, JJ
;
Chiang, CC
This work examines the thermal stability of Ta barrier layer for Cu metallization with the effect of oxygen. The Cu/Ta/SiO2/Si films were annealed at temperatures ranging from 400 to 600 degreesC under various vacuum conditions. Transmission electron microscopy has been performed to characterize the microstructure of the films after annealing. The results show that an amorphous interlayer of oxide between Cu and Ta can be formed at 400 degreesC in a vacuum of 10(-2) mbar. X-Ray energy dispersive spectroscopy and electron energy loss spectroscopy confirm that this interlayer is tantalum oxide. This interlayer transformed into a crystalline phase of Ta-Cu oxide at 600 degreesC. In addition, formation of tantalum oxide interlayer is more thermodynamically favorable than that of copper oxide layer at the Cu/Ta interface. Growth of the amorphous interlayer is atmosphere-dependent, as evidenced by the thickness of tantalum oxide being decreased with better vacuum or argon gas. This observation suggests that the oxidation source may arise from the annealing atmosphere rather than from interior SiO2. Furthermore, it has been observed that oxygen diffuses along grain boundaries in copper films to cause tantalum oxidation. (C) 2001 Elsevier Science B.V. All rights reserved.
Physical and barrier properties of amorphous silicon-oxycarbide deposited by PECVD from octamethylcyclotetrasiloxane
(2004)
Chiang, CC
;
Chen, CC
;
Li, LJ
;
Wu, ZC
;
Jang, SM
This work investigates the thermal stability and physical and barrier properties for three species of amorphous silicon-oxycarbide (alpha-SiCO) dielectric barrier films, deposited by plasma-enhanced chemical vapor deposition (PECVD), to copper (Cu) diffusion using octamethylcyclotetrasiloxane precursor and helium (He) carrier gas with and without oxygen (O-2) reaction gas. The alpha-SiCO dielectric barrier film deposited by PECVD without O-2 reaction gas exhibits a low k-value of 2.8, thermally stable at temperatures up to 550 degreesC, excellent moisture resistance, and superb Cu barrier property until 400 degreesC. With the addition of O-2 reaction gas during the dielectric deposition process, the dielectric constant of the alpha-SiCO dielectric barrier films increases with increasing flow rate of O-2 reaction gas. Increasing flow rate of O-2 reaction gas during the deposition of the alpha-SiCO dielectric barrier films also degrades the thermal stability and moisture resistance of the dielectric barrier films. Moreover, the addition of O-2 reaction gas also results in a degraded Cu barrier property of dielectric films. (C) 2004 The Electrochemical Society.
Physical and barrier properties of PECVD amorphous silicon-oxycarbide from trimethylsilane and CO2
(2004)
Chiang, CC
;
Ko, IH
;
Chen, MC
;
Wu, ZC
;
Lu, YC
This work investigates the thermal stability and physical and barrier properties of amorphous silicon-carbide (alpha-SiC) and amorphous silicon-oxycarbide (alpha-SiCO) dielectric barriers deposited by plasma-enhanced chemical vapor deposition (PECVD) using trimethylsilane (3MS) precursor and He carrier gas. Films were deposited without and with various CO2 flow rates. The dielectric constant of the alpha-SiCO films decreased with increasing CO2 flow rate. Increasing CO2 flow rate also promotes better thermal stability, higher breakdown field, lower leakage current, and superior resistance to Cu diffusion through the films. The improved barrier property is attributed to the denser and less porous structure of the alpha-SiCO dielectric barrier upon CO2 addition. The alpha-SiCO barrier films deposited with the large (1200 Seem) CO2 flow rate exhibit the low k value of 3.7, thermal stability up to 550degreesC, room-temperature breakdown field of 8 MV/cm and leakage current densities of 10(-7) to 10(-6) A/cm(2) at 3 MV/cm, and a superb Cu barrier property. (C) 2004 The Electrochemical Society.
Physical and barrier properties of plasma enhanced chemical vapor deposition alpha-SiC : N : H films
(2003-07-01)
Chiang, CC
;
Wu, ZC
;
Wu, WH
;
Chen, MC
;
Ko, CC
In this work, we investigate the thermal stability and physical and barrier properties of three species of plasma enhanced chemical vapor deposition (PECVD) alpha-SiC:N:H silicon carbide films with different carbon and nitrogen contents and dielectric constants less than a value of 5.5. For comparison, one species of alpha-SiN:H film with a k value of 7.2 is also studied. It is found that the dielectric constant decreases with increasing content of carbon and decreasing content of nitrogen in the alpha-SiC:N:H film. All of the three species of alpha-SiC:N:H and the one species of alpha-SiN:H films are thermally stable at temperatures up to 500degreesC. However, degraded barrier capability and moisture resistance were observed for the alpha-SiC:N:H film with a k value of 3.5, which has a C/Si atomic ratio of 0.875. This is presumably due to the poorly crosslinked molecular structure and porosity enhancement caused by the abundant amount of carbon in the alphaSiC:N:H film.
Physical and barrier properties of plasma-enhanced chemical vapor deposited alpha-SiC : H films from trimethylsilane and tetramethylsilane
(2003-07-01)
Chiang, CC
;
Chen, MC
;
Ko, CC
;
Wu, ZC
;
Jang, SM
This work investigates the thermal stability and physical and barrier properties of two species of plasma-enhanced chemical vapor deposited (PECVD) alpha-SiC:H silicon carbide films (with k-values less than 5) deposited using trimethylsilane, (CH3)(3)SiH (3MS) and tetramethylsilane, (CH3)(4)Si (4MS) organosilicate gases. It is found that the 4MS alpha-SiC:H film contains a higher content of carbon and has a lower dielectric constant. Both of the 3MS and 4MS alpha-SiC:H films are thermally stable at temperatures up to 500degreesC. However, degraded barrier property and moisture resistance were observed for the 4MS alpha-SiC:H film; this is attributed to the porosity enrichment caused by the film's high carbon content. The 3MS alpha-SiC:H film, which exhibits a superior Cu-barrier property, is a potential candidate for replacing the higher dielectric constant Si3N4 film as a Cu-cap barrier and etching stop layer in the Cu damascene structure.
Physical and barrier properties of plasma-enhanced chemical vapor deposited alpha-SiCN : H films with different hydrogen contents
(2003-08-01)
Chiang, CC
;
Chen, MC
;
Ko, CC
;
Jang, SM
;
Yu, CH
This work investigates the thermal stability and physical and barrier properties of two species of plasma-enhanced chemical-vapor-deposited (PECVD) amorphous silicon-nitrocarbide (alpha-SiCN:H) films with different hydrogen contents and dielectric constants of less than 5. It is found that the alpha-SiCN:H film with a higher hydrogen content has a lower dielectric constant. Both species of alpha-SiCN:H films are thermally stable at temperatures up to 500degreesC. However, a degraded dielectric strength was observed for the alpha-SiCN:H film with a lower k-value of 4, which has a much higher hydrogen content. This may be attributed to hydrogen-related defects, such as Si-H+-Si hydrogen bridges, and numerous Si-H weak bonds produced by the high hydrogen content in the alpha-SiCN:H film.
Physical and electrical characteristics of F- and C-doped low dielectric constant chemical vapor deposited oxides
(2001-06-01)
Wu, ZC
;
Shiung, ZW
;
Chiang, CC
;
Wu, WH
;
Chen, MC
This work compares the physical and electrical properties of two species of inorganic low dielectric constant (low-k) chemical vapor deposited (CVD) oxides, F-doped fluorinated silicate glass (FSG, k = 3.5) and C-doped organosilicate glass (OSG, k = 2.9). Experimental results indicate that FSG has a higher thermal stability >600 degreesC! than OSG (500 degreesC), based on the results of thermal annealing for 30 min in an N-2 ambient. The degradation of the low-k property in OSG is mainly due to the thermal decomposition of methyl (-CH3) groups at temperatures above 500 degreesC. For the Cu gated oxide-sandwiched low-k dielectric metal-insulator-semiconductor (MIS) capacitors, Cu penetration was observed in both FSG and OSG after the MIS capacitors were bias-temperature stressed at 250 and 150 degreesC, respectively, with an effective applied field of 0.8 MV/cm. Specifically, Cu appeared to drift more readily in OSG than in FSG, presumably because OSG has a more porous and less dense structure than FSG. The Cu permeation can be impeded by a thin nitride (SiN) barrier layer. (C) 2001 The Electrochemical Society.
Physical and electrical characteristics of methylsilane- and trimethylsilane-doped low dielectric constant chemical vapor deposited oxides
(2001-06-01)
Wu, ZC
;
Shiung, ZW
;
Chiang, CC
;
Wu, WH
;
Chen, MC
This work investigates the physical and electrical properties of two species of inorganic C-doped low dielectric constant (low-k) chemical vapor deposited (CVD) organosilicate glasses (OSGs, alpha -SiCO:H). They are both deposited by plasma-enhanced CVD (PECVD) processes using methylsilane [(CH3)SiH3, 1 MS]- and trimethylsilane [(CH3)(3)SiH, 3 MS]-based gases as the reagents, and are designated as OSG1 and OSG2, respectively. Experimental results indicate that the thermal stability temperature of OSG1 is 500 degreesC, while that of OSG2 is 600 degreesC, based on the results of thermal annealing for 30 min in an N-2 ambient. The deterioration of the low-k property in OSG1 is predominately due to the thermal decomposition at temperatures above 500 degreesC of methyl (-CH3) groups, which are introduced to lower the density and polarizability of OSGs. For the Cu-gated oxide-sandwiched low-k dielectric metal-insulator-semiconductor (MIS) capacitors, Cu permeation was observed in both OSG1 and OSG2 after the MIS capacitors were bias-temperature stressed at 150 degreesC with an effective applied field of 0.8 MV/cm. Moreover, Cu appeared to drift more readily in OSG1 than in OSG2, presumably because OSG1 has a more porous and less cross-linked structure than OSG2. The Cu penetration can be mitigated by a thin nitride dielectric barrier. (C) 2001 The Electrochemical Society.
TDDB reliability improvement in Cu damascene by using a bilayer-structured PECVD SiC dielectric barrier
(2002)
Chiang, CC
;
Chen, MC
;
Wu, ZC
;
Li, LJ
;
Jang, SM
This work investigates the thermal stability and barrier characteristics of two species of silicon carbide dielectric films, alpha-SiCN with a dielectric constant of 4.9 and alpha-SiC with a dielectric constant of 3.8. The TDDB lifetime of Cu damascene metallization structure is greatly improved by using a alpha-SiCN/alpha-SiC bilayer dielectric stack as the etching stop layer (ESL). This improvement is presumably due to the alpha-SiC dielectric's lower leakage current, absence of nitridation on Cu surface, and better adhesion on Cu as well as OSG intermetal dielectric (IMD), though the alpha-SiC film has a very slow deposition rate. We believe that the alpha-SiCN/alpha-SiC bilayer dielectric is a favorable combination for the ESL because alpha-SiCN can protect alpha-SiC from plasma attack during the photoresist stripping.