Browsing by Author "Lee, C"

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A comparative study of Ar and H-2 as carrier gases for the growth of SiC films on Si(100) by electron cyclotron resonance chemical vapor deposition at low temperature
(2001-11-01)
Lee, WH
;
Lin, JC
;
Lee, C
;
Cheng, HC
;
Yew, TR
Electron cyclotron resonance chemical vapor deposition (ECR-CVD) of SiC films from silane and methane gas mixtures at low temperature has been investigated using two different carrier gases, namely, argon and hydrogen. The results obtained are compared. The chemical composition and crystalline microstructure were investigated by Fourier transform infrared spectroscopy (FTIR) and cross-sectional transmission electron microscopy (XTEM), respectively. The results indicate that the carrier gases have a greater influence on the film composition and microstructure as compared to the growth parameters like pressure, power and flow ratio. The deposition mechanism which controls the film characteristics is also presented. (C) 2001 Elsevier Science B.V. All rights reserved.
Characteristics of MOCVD- and MBE-grown InGa(N)As VCSELs
(2005-08-01)
Yang, HPD
;
Lu, C
;
Hsiao, R
;
Chiou, C
;
Lee, C
We report our results on InGaNAs/GaAs vertical-cavity surface-emitting lasers (VCSELs) in the 1.3 mu m range. The epitaxial structures were grown on (10 0) GaAs substrates by metalorganic chemical vapour deposition (MOCVD) or molecular beam epitaxy (MBE). The nitrogen composition of the InGa(N)As/GaAs quantum-well (QW) active region is 0-0.02. The long-wavelength (up to 1.3 mu m) room-temperature continuous-wave (RT CW) lasing operation was achieved for MBE- and MOCVD-grown VCSELs. For MOCVD-grown devices with n- and p-doped distributed Bragg reflectors (DBRs), a maximum optical output power of 0.74 mW was measured for In(0.36)Ga(0.64)N(0.006)AS(0.994)/GaAs VCSELs. A very low J(th) of 2.55 kA cm(-2) was obtained for the InGaNAs/GaAs VCSELs. The MBE-grown devices were made with an intracavity structure. Top-emitting multi-mode 1.3 mu m In0.35Ga0.65N0.02As0.98/GaAs VCSELs with 1 mW output power have been achieved under RT CW operation. A J(th) of 1.52 kA cm-2 has been obtained for the MBE-grown In0.35Ga0.65N0.02As0.98/GaAs VCSELs, which is the lowest threshold current density reported. The emission characteristics of the InGaNAs/GaAs VCSELs were measured and analysed.
Dea approach for the current and the cross period efficiency for evaluating the vocational education
(2004-06-01)
Liu, LC
;
Lee, C
;
Tzeng, GH
;
科技管理研究所
;
Institute of Management of Technology
This study proposes an improved assessment system for vocational education, thus helping to increase technology college education efficiency. Data Envelopment Analysis (DEA) was used to examine the relative managerial efficiency for evaluating current-period and cross-period efficiency of 38 technological institutes upgraded from junior colleges in Taiwan by 1998. In addition, the managerial efficiency variations of each individual institute in between 1995 and 1998 were also determined. The study results show that the operational category is significant among primary analysis variants, i.e. private schools perform significantly better than public schools in terms of managerial efficiency. However, geographical location is not significant. This study also verifies that integration of the results of both relative managerial efficiency analysis and managerial efficiency variation analysis could, be a powerful approach to help design managerial strategies that are both appropriate and effective. Some strategies to improve organization-wide operational competencies for site decision-makers axe recommended, and a new way of thinking to construct a more appropriate evaluation system for the educational authorities is introduced.
Design and implementation of ultra-low latency optical label switching for packet-switched WDM networks
(2000-12-01)
Meagher, B
;
Chang, GK
;
Ellinas, G
;
Lin, YM
;
Xin, W
An ultra-low latency, high throughput internet protocol(IP) over wavelength division multiplexing (WDM) packet switching technology for next-generation internet (NGI) applications has been designed and demonstrated. This method overcomes limitations of conventional optical packet switching, which require buffering of packets and synchronization of bits, rind optical burst switching methods that require estimation of delays at each node and for each path. An optical label switching technique was developed to realize flexible bandwidth-on-demand packet transport on a reconfigurable WDM network. The aim was to design a network with simplified protocol stacks, scalability, and data transparency, This network will enable the NGI users to send their data applications at gigabit/second access speed with low and predictable latency (<1 sec per switch node), with a system capacity of beyond multi-Tb/s. Packet forwarding utilizes WDM optical headers that are carried in-band on the same wavelength and modulated out-of-hand in the frequency domain.
Development of low-temperature wafer level vacuum packaging for microsensors
(1999)
Huang, WF
;
Shie, JS
;
Lee, C
;
Gong, SC
;
Peng, CJ
Wafer level packaging received lots of attention in microsystems recently. Because it shows the potential to reduce the packaging cost, while the yield of devices after dicing and packaging can be increased. However, there is a limitation of commercialized wafer bonding technology, i.e., the high process temperature, such as 1000 degrees C of silicon fusion bonding, and 450 degrees C of anodic bonding. A novel low temperature wafer bonding with process temperature lower than 160 degrees C is proposed, it applies the In-Sn alloy to form the interface of wafer bonding. The experiment results show helium leak test of 6x10(-9)torr-liter/sec, and a tensile strength as high as 200kg/cm(2). Reliability test after 1500 temperature cycles between -10 to 80 degrees C also shows no trace of degradation compared to the initial quality of the samples. This low temperature soldering process demonstrates its promising potential at the wafer level packaging in industrial production.
Effects of CH4/SiH4 flow ratio and microwave power on the growth of beta-SiC on Si by ECR-CVD using CH4/SiH4/Ar at 200 degrees C
(2002-02-22)
Lee, WH
;
Lin, JC
;
Lee, C
;
Cheng, HC
;
Yew, TR
The effects of CH4/SiH4 flow ratio and microwave power on the formation of SiC at 200 degreesC by electron cyclotron resonance chemical vapor deposition is investigated. When the CH4/SiH4 flow ratio is varied from 0.5 to 10, crystalline phase of films vary from polycrystalline silicon to polycrystalline P-SiC and finally to amorphous silicon carbide. However, as the microwave power increases from 300 to 1500 W. the film microstructure changes from polycrystalline Si to amorphous SiC. and finally to polycrystalline beta-SiC. The deposition mechanism which controls the film characteristics is also presented. (C) 2002 Elsevier Science B.V. All rights reserved.
Low temperature deposited highly-conductive N-type SiC thin films
(1997)
Cheng, KL
;
Cheng, HC
;
Lee, WH
;
Lee, C
;
Yew, TR
Low-temperature deposited highly-conductive SiC films has long been a goal for many researchers involved in hetero-junction bipolar transistor, thin-film transistor, solar cell...etc. Were in this paper, we study the influences of the diluted PH3 now rates on SiC film quality as well as electrical properties. PH+ was determined from residual gas analyzer to be the main dopant source. Phosphorous atoms will play a role of enhancing the SiC grain growth and resulting in a smaller film growth rate. Carrier concentrations increase monotonically with the diluted PH; now rates. While Hall mobility first increases than decreases with it due to a combination effect of the impurity scattering and a film quality improvement which dominates when the 1% PH3/H-2 flow rate is above or below 40 seem, respectively.
Polycrystalline beta-SiC film growth on Si by ECR-CVD at 178-500 degrees C
(1996)
Cheng, KL
;
Liu, CC
;
Fu, CM
;
Cheng, HC
;
Lee, C
Wafer bonding by low-temperature soldering
(2000-08-25)
Lee, C
;
Huang, WF
;
Shie, JS
;
光電工程學系
;
Department of Photonics
Recently. wafer level packaging received lots of attention in microsystems because it shows the potential to reduce the packaging cost, while the yield of devices after dicing and packaging can be increased. However, there is a limitation of commercialized wafer bonding technology. i.e., the high process temperature, such as 1000 degrees C of silicon fusion bonding, and 450 degrees C of anodic bonding. A novel tow-temperature wafer bonding with process temperature lower than 160 degrees C is proposed, it applies the In-Sn alloy to form the interface of wafer bonding. The experiment results show helium leak test of 6 x 10(-9) Torr 1/s, and a tensile strength as high as 200 kg/cm(2). Reliability test after 1500 temperature cycles between -10 degrees C and 80 degrees C also shows no trace of degradation compared to the initial quality of the samples. This low-temperature soldering process demonstrates its promising potential at the wafer level packaging in industrial production. (C) 2000 Elsevier Science. S.A. All rights reserved.