Browsing by Author "Chang, H. L."

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AlGaInAs/InP eye-safe laser pumped by a Q-switched Nd:GdVO(4) laser
(2009-03-01)
Huang, S. C.
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Chang, H. L.
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Su, K. W.
;
Li, A.
;
Liu, S. C.
An AlGaInAs quantum-well structure grown on a Fe-doped InP transparent substrate is developed to be a gain medium in a high-peak-power nanosecond laser at 1570 nm. Using an actively Q-witched 1064 nm laser to pump the gain chip, an average output power of 135 mW is generated at a pulse repetition rate of 30 kHz and an average pump power of 1.25 W. At a pulse repetition rate of 20 kHz, the peak output power is up to 290 W at a peak pump power of 2.3 kW.
AlGaInAs/InP eye-safe laser pumped by a Q-switched Nd:GdVO4 laser
(2009-03-01)
Huang, S. C.
;
Chang, H. L.
;
Su, K. W.
;
Li, A.
;
Liu, S. C.
An AlGaInAs quantum-well structure grown on a Fe-doped InP transparent substrate is developed to be a gain medium in a high-peak-power nanosecond laser at 1570 nm. Using an actively Q-witched 1064 nm laser to pump the gain chip, an average output power of 135 mW is generated at a pulse repetition rate of 30 kHz and an average pump power of 1.25 W. At a pulse repetition rate of 20 kHz, the peak output power is up to 290 W at a peak pump power of 2.3 kW.
Compact efficient Q-switched eye-safe laser at 1525 nm with a double-end diffusion-bonded Nd:YVO(4) crystal as a self-Raman medium
(2009-03-16)
Chang, Y. T.
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Su, K. W.
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Chang, H. L.
;
Chen, Y. F.
;
電子物理學系
We report on an efficient Q-switched eye-safe laser at 1525 nm with a double-end diffusion-bonded Nd:YVO(4) crystal as a self-Raman gain medium. A diffusion-bonded crystal not only reduces the thermal effects but also increase the interaction length for the stimulated Raman scattering. With an input pump power of 17.2 W, average power of 2.23 W at the first-Stokes wavelength of 1525 nm is generated at a pulse repetition rate of 40 kHz, corresponding to a conversion efficiency of 13%. (C) 2009 Optical Society of America
Compact efficient Q-switched eye-safe laser at 1525 nm with a double-end diffusion-bonded Nd:YVO4 crystal as a self-Raman medium
(2009-03-16)
Chang, Y. T.
;
Su, K. W.
;
Chang, H. L.
;
Chen, Y. F.
;
電子物理學系
We report on an efficient Q-switched eye-safe laser at 1525 nm with a double-end diffusion-bonded Nd:YVO4 crystal as a self-Raman gain medium. A diffusion-bonded crystal not only reduces the thermal effects but also increase the interaction length for the stimulated Raman scattering. With an input pump power of 17.2 W, average power of 2.23 W at the first-Stokes wavelength of 1525 nm is generated at a pulse repetition rate of 40 kHz, corresponding to a conversion efficiency of 13%. (C) 2009 Optical Society of America
CRYSTALLIZATION AND FAILURE BEHAVIORS OF Ta-Co NANOSTRUCTURED/AMORPHOUS DIFFUSION BARRIERS FOR COPPER METALLIZATION
(2003-12-01)
Fang, J. S.
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Chang, H. L.
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Chen, G. S.
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Lee, P. Y.
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材料科學與工程學系
This work examines the thin-film properties and diffusion barrier behaviors of thin Ta-Co films, aiming at depositing highly crystallization-resistant and highly conductive diffusion barriers for Cu metallization. Structure analyzing indicates that the deposited Ta-Co films indeed have a glassy structure and are free from highly resistive intermetallic compounds, thus giving a low resisitivity under 20 mu Omega-cm. Examining Si/Ta-Co/Cu stacked samples by using 4-point probes and XRD reveals that thermally induced failure of amorphous Ta-Co barriers are triggered by the barrier\'s crystallization at temperatures just under around 600 degrees C. The effectiveness of the nanostructure/amorphous Ta-Co thin film thus can be substantially enhanced by effectively blocking diffusion of copper towards the underlying silicon.
Efficient high-peak-power AlGaInAs eye-safe wavelength disk laser with optical in-well pumping
(2009-07-06)
Chang, H. L.
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Huang, S. C.
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Chen, Yi-Fan
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Su, K. W.
;
Chen, Y. F.
We have demonstrated an efficient high-peak-power AlGaInAs eye-safe wavelength disk laser at 1555 nm. The quantum defect and the thermal load are significantly reduced by pumping the quantum well directly. The overall conversion efficiency is enhanced over three times compared with the barrier pumping method. With a pump peak power of 3.7 kW, an output peak power of 0.52 kW is generated at a pulse repetition rate of 20 kHz. (C) 2009 Optical Society of America
High-efficiency Q-switched dual-wavelength emission at 1176 and 559 nm with intracavity Raman and sum-frequency generation
(2009-07-06)
Chang, Y. T.
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Chang, H. L.
;
Su, K. W.
;
Chen, Y. F.
;
電子物理學系
An efficient Q-switched dual-wavelength laser with self-frequency Raman conversion in composite Nd:YVO(4) and intracavity sum-frequency generation in BBO is reported. With an input pump power of 17.5 W, average power of 0.53 W at the first-Stokes 1176 nm and average power of 1.67 W at the sum-frequency mixed 559 nm are simultaneously generated at a pulse repetition rate of 100 kHz, corresponding to a total conversion efficiency of 12.5%. (C) 2009 Optical Society of America
Improving TDDB Reliability in Cu Damascene by modulating ESL Structure
(2012)
Chang, C. T.
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Chang, H. L.
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材料科學與工程學系
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Department of Materials Science and Engineering
Low k time-dependent dielectric breakdown (TDDB) is increasing becoming a major issue at 28 nm and beyond. Although TDDB models, such as E model, the root E model and the 1/E model, have been extensively explored, determining the BEOL processing direction for TDDB warrants further study. This study attempts to determine whether the thickness of the etching stop layer film influences the electron conduction mechanism. Cu damascene structures were designed following three approaches with ESL in various thicknesses. They were Co/ESL=0A-550A (LK: SiCO k= 3.1), Cu/ESL=0A-275A (ELK: SiCO k=2.5) and Co/ESL=0A-275A (ELK: SiCO k=2.5). Analytical results demonstrated superior breakdown fields of 8.5 MV/cm, 7.5 MV/cm and 7.5 MV/cm for Co/ESL=0A (SiCO k=3.1), Cu/ESL =0A (SiCO k=2.5) and Co/ESL =0A (SiCO k=2.5), respectively. TDDB results further reveal that the ESL=0A structure is essential to a long TDDB lifetime, because electrons are conducted through the ESL bulk film. The mechanism of TDDB improvement is considered to be the absence of ESL, the modified metal/LK electrical potential and the negligibility of interfacial LK/LK surface defects.
Mechanical properties and fracture mechanism of porous SiOCH low-k dielectrics
(2011-07-01)
Chang, H. L.
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Kuo, C. T.
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Liang, M. S.
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材料科學與工程學系
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高階主管管理碩士學程
A series of low-k dielectric films with various mechanical properties were prepared for a 32-nm back-end-of-line technology node. Various precursors were used, and the porogen removal treatment was performed using the H(2) or E-beam-assisted method. This study presents a novel approach for determining the loss of materials during treatment. This approach includes determining yield strength, fracture toughness, bonding structure, and fracture mechanism of a series of low-k silica films. The results show that a low-k film formed using the precursor trimethylsilane has higher yield strength and fracture toughness than the low-k films formed using the precursor tetramethylsilane or octamethylcyclotetrasiloxane. The residual gas analysis was conducted to determine the loss of materials and predict the bonding structure: the results show that the E-beam treatment rearranges the structure more effectively than the H(2) treatment by using the H radial to decompose the methyl group. Finally, the fracture mechanism of these low-k films was determined by relating the crack patterns of the indents on these films to their indentation load-displacement curves. (C) 2011 Elsevier B.V. All rights reserved.
Nanostructured Material Formation for Beyond Si Devices
(2015)
Chang, H. L.
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Chang, C. T.
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Kuo, C. T.
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材料科學與工程學系
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Department of Materials Science and Engineering
Beyond Si CMOS technology is the current challenging for next generation transistor. As demand for nano-scaled devices increase, the ability to manipulate the building blocks of electronic is essential. Catalytic-assisted CNTs are integrated into trenches, holes, parallel plates under CH4/H-2 gases by microwave plasma chemical vapor deposition or electron cyclotron resonance deposition. The trench and parallel plates are used to fabricate for gate electrodes, while the holes are used to make interconnections. Results indicate the orientation of grown CNTs is dominated by pattern geometry. The field emission results show that the CNTs exhibit robust electronic properties with emission densities of over 1mA/cm(2) at 3.97 and 6.30 V/mu m indicating the high electron emission efficiency as the CNT field effect transistor application. The growth models of Fe, Ni and CoSi2 and application for nanoclectronics are purposed.
Oxygen vacancy estimation of high k metal gate using thermal dynamic model
(2010-07-26)
Chang, H. L.
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Liang, M. S.
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材料科學與工程學系
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Department of Materials Science and Engineering
Oxygen vacancies are electronic defects in materials. In a metal oxide system, the distribution of such vacancies is determined by the oxygen affinity. This study predicts the oxygen vacancy concentration in a high-k/metal gate system using a developed thermal dynamic model. A system with Ti:N=2 has a 200 mV lower flat band voltage than an N rich metal. The Gibbs free energy of formation of oxygen vacancies, similar to 0.5 eV, is derived from flab band voltage shifts and created neutral oxygen vacancy. The oxygen vacancy model based on estimating thermal dynamics is proposed. (C) 2010 American Institute of Physics. [doi:10.1063/1.3473772]
Passive Q switching of Er-Yb fiber laser with semiconductor saturable absorber
(2008-03-03)
Huang, J. Y.
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Huang, S. C.
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Chang, H. L.
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Su, K. W.
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Chen, Y. F.
A high-performance A1GaInAs quantum-well saturable absorber is developed for passively Q-switched Er-Yb double-clad fiber lasers at 1560 nm. With an incident pump power of 13.5 W, an average output power of 1.26 W with a pulse repetition rate of 12 kHz is obtained. The maximum peak power is greater than 500 W. (C) 2008 Optical Society of America.
Self-mode-locked Nd:GdVO(4) laser with multi-GHz oscillations: manifestation of third-order nonlinearity
(2009-10-01)
Liang, H. C.
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Chang, H. L.
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Huang, W. C.
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Su, K. W.
;
Chen, Y. F.
The large third-order nonlinearity of GdVO(4) crystals is employed to realize the compact efficient continuous-wave self-mode locking in the range of several GHz in a Nd:GdVO(4) laser with a simple linear cavity without the need of any additional components. With a pump power of 2.5 W, the compact laser cavity produces average output powers greater than 0.7 W with a pulse width as short as 23 ps in the range of 2-6 GHz.
Self-mode-locked Nd:GdVO4 laser with multi-GHz oscillations: manifestation of third-order nonlinearity
(2009-10-01)
Liang, H. C.
;
Chang, H. L.
;
Huang, W. C.
;
Su, K. W.
;
Chen, Y. F.
The large third-order nonlinearity of GdVO4 crystals is employed to realize the compact efficient continuous-wave self-mode locking in the range of several GHz in a Nd:GdVO4 laser with a simple linear cavity without the need of any additional components. With a pump power of 2.5 W, the compact laser cavity produces average output powers greater than 0.7 W with a pulse width as short as 23 ps in the range of 2-6 GHz.
Study of Conduction Modes of Time to Dielectric Breakdown Reliability in Cu Damascene Structures
(2013)
Chang, H. L.
;
Chang, C. T.
;
Kuo, C. T.
;
材料科學與工程學系
;
Department of Materials Science and Engineering
Low k time-dependent dielectric breakdown is increasingly becoming a major issue at the 45 nm technology node and beyond. Although TDDB models, such as the root E model, the v E model and the 1/E model, have been extensively explored, determining the back end of line processing direction for TDDB warrants further study. This study attempts to determine whether the thickness of the etching stop layer film influences the electron conduction mechanism. Cu damascene structures were designed following three approaches with various thickness of the etching stop layer : Co/ESL = 0 A-550 A (low-k: SiCO k = 3.1), Cu/ESL = 0 A-275 A (low-k: SiCO k = 2.5) and Co/ESL = 0 A-275 A (low-k: SiCO k = 2.5). The application of capping material Co is warranted for electron emission suppression, but the oxygen attacking from subsequent low-k deposition is a concern. In addition, greater ESL thickness offers paths for electron conduction which worsens TDDB; i.e., less ESL thickness is better. Therefore, the combination of Co with SiH4 treatment addresses optimized conditions to achieve an ESL-less application for TDDB enhancement. (C) 2013 The Electrochemical Society. All rights reserved.
Subnanosecond mJ eye-safe laser with an intracavity optical parametric oscillator in a shared resonator
(2009-02-02)
Huang, Y. P.
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Chang, H. L.
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Huang, Y. J.
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Chang, Y. T.
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Su, K. W.
We theoretically verify that the threshold of an intracavity optical parametric oscillator pumped by a passively Q-switched laser is entirely controlled by the bleach of the saturable absorber not by the signal output reflectivity. We use a series of different output couplers to optimize the output performance. With a signal output reflectivity of 15%, we experimentally achieve an efficient subnanosecond eye-safe laser with 3.3 mJ pulse energy and 1.5 MW peak power. @ 2008 Optical Society of America
Widely tunable eye-safe laser by a passively Q-switched photonic crystal fiber laser and an external-cavity optical parametric oscillator
(2011-09-01)
Chang, H. L.
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Zhuang, W. Z.
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Huang, W. C.
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Huang, J. Y.
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Huang, K. F.
We report on a widely tunable passively Q-switched photonic crystal fiber (PCF) laser with wavelength tuning range up to 80 nm. The PCF laser utilizes an AlGaInAs quantum well/barrier structure as a saturable absorber and incorporates an external-cavity optical parametric oscillator (OPO) to achieve wavelength conversion. Under a pump power of 13.1 W at 976 nm, the PCF laser generated 1029-nm radiation with maximum output energy of 750 mu J and was incident into an external-cavity OPO. The output energy and peak power of signal wave was found to be 138 mu J and 19 kW, respectively. By tuning the temperature of nonlinear crystal, periodically poled lithium niobate (PPLN), in the OPO, the signal wavelength in eye-safe regime from 1513 to 1593 nm was obtained. (C) 2011 by Astro Ltd. Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA