Browsing by Author "Lai, CH"

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A novel program-erasable high-(K) A1N-Si MIS capacitor
(2005-03-01)
Lai, CH
;
Chin, A
;
Hung, BF
;
Cheng, CF
;
Yoo, WJ
We demonstrate a programmable-erasable MIS capacitor with a single layer high-kappa AIN dielectric on Si having a high capacitance density of 5 fF/mum(2). It has low program and erase voltages of +4 and -4 V, respectively. Such an erase function is not available in other single layer Al2O3, AION, or other known high-kappa dielectric capacitors, where the threshold voltage (T h) shifts continuously with voltage. This device exhibits good data retention with a V-th change of only 0.06 V after 10 000 s.
A quantum trap MONOS memory device using AlN
(2006)
Lai, CH
;
Wu, CH
;
Chin, A
;
Wang, SJ
;
McAlister, SP
We report a IrO2-HfAlO-AlN-SiO2-Si MONOS device that displays excellent characteristics in terms of speed (100 mu s at +/- 13 V for program/erase) and memory window (3.7 V) at 85 degrees C operation. This device also shows good 10-year extrapolated data retention with a large 1.9 V window at 85 degrees C. The achieved performance compares well with the best reported memory device data. (c) 2006 The Electrochemical Society.
A tunable and program-erasable capacitor on Si with excellent tuning memory
(2004)
Lai, CH
;
Lee, CF
;
Chin, A
;
Zhu, C
;
Li, MF
A novel tunable and program-erasable high-kappa: AIN MIS capacitor is demonstrated for the first time with excellent tuning memory, which is useful to tune the impedance mismatching and resonance frequency without always connected voltage bias circuit. Large C-max /C-min tunability of 12 is obtained due to the high-kappa AIN dielectric with high 5 muF/mum(2) capacitance density. Good tuning memory is evidenced from the small V-th variation after program or erase at +4 V or -4 V for 10,000 s and the potential of years long extrapolated memory time.
Anisotropy transition of Co in IrMn/Co/FeOx/Co by field cooling
(2006-04-15)
Shen, CT
;
Lai, CH
;
Huang, PH
;
Hsu, SY
;
Chung, TY
The temperature dependence of Co anisotropy on a nano-FeOx layer was studied in the structure of IrMn/Co (FM1)/FeOx/Co (FM2). An anisotropy transition of the FM2 was observed from a combination of uniaxial and unidirectional anisotropies at room temperature (RT) to unidirectional anisotropy at temperature below 80 K through field cooling process. Various ferromagnetic (FM) and antiferromagnetic (AFM) components existing in the FeOx layer were attributable to the observed anisotropy of FM2. AFM domains with T-N higher than room temperature were responsible for the observed uniaxial anisotropy at RT and AFM domains with T-N of 80 K were accountable for the anisotropy transition, below which the unidirectional anisotropy became dominant. In addition, the direction of the shifted loop could be determined by the cooling field direction. (C) 2006 American Institute of Physics.
DSP-embedded UPS controller for high-performance single-phase on-line UPS systems
(2002)
Lai, CH
;
Tzou, YY
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This paper proposes a DSP-controlled transformerless common-neutral single-phase on-line UPS with balanced charging/discharging control. All the control functions for an on-line UPS, which includes power-on start-up control, input stage power factor control, battery charging and boosting control, output stage ac voltage regulation, and shut-down control, were realized by using a single-chip DSP controller. A multiple rate digital controller generates all the PWM control signals for the power stage by using a set of detected feedback signals. Software current control scheme with nonlinear pulsewidth compensation has been developed to eliminate the nonlinearity caused by the dead-lock protected PWM converters. A nonlinear digital control scheme with lower switching frequency has been developed for the power factor control of the ac-dc converter. Computer simulation and experimental results have been given to verify the proposed digital control scheme. The constructed DSP-controlled UPS system can achieve fast dynamic response for nonlinear loads and high power factor under various loading conditions.
Formation of Ni germano-silicide on single crystalline Si0.3Ge0.7/Si
(2002-08-01)
Lin, CY
;
Chen, WJ
;
Lai, CH
;
Chin, A
;
Liu, J
We have studied the Ni and Co germano-silicide on Si0.3Ge0.7/Si. The Ni germano-silicide shows a low sheet resistance of 4-6 Omega/square on both P+N and N+P junctions, which is much smaller than Co germano-silicide. In addition, small junction leakage currents of 3 x 10(-8) A/cm(2) and 2 x 10(-7) A/cm(2) are obtained for Ni germano-silicide on P+ N and N+ P junctions, respectively. The good germano-silicide integrity is due to the relatively uniform thickness as observed by cross-sectional TEM.
Frequency-dependent capacitance reduction in high-k AlTiOx and Al2O3 gate dielectrics from IF to RF frequency range
(2002-04-01)
Chen, SB
;
Lai, CH
;
Chan, KT
;
Chin, A
;
Hsieh, JC
We have characterized the capacitance and loss tangent for high-k Al2O3 and AlTiOx gate dielectrics from IF (100 KHz) to RF (20 GHz) frequency range. Nearly the same rate of capacitance reduction as SiO2 was demonstrated individually by the proposed Al2O3 and AlTiOx gate dielectrics as frequency was increased. Moreover, both dielectrics preserve the higher k better than SiO2 from 100 KHz to 20 GHz. These results suggest that both Al2O3 and AlTiOx are suitable for next generation MOSFET application into RF frequency regime.
High interfacial exchange energy in TbFeCo exchange-bias films
(2003-05-15)
Lin, CC
;
Lai, CH
;
Jiang, RF
;
Shieh, HPD
;
光電工程學系
The exchange-bias films of ferrimagnetic/ferrimagnetic, ferromagnetic/ferromagnetic, and ferromagnetic/antiferromagnetic bilayers were fabricated to investigate their interfacial exchange energy Deltasigma. Deltasigma of TbFeCo bilayers is larger than 5 erg/cm(2) at room temperature. By varying the composition of TbFeCo layers, both positive and negative exchange bias have been observed. A highly uncompensated-spin interface model was proposed to explain the strong exchange interaction in TbFeCo bilayers. Due to the characteristics of highly uncompensated-spin interface at TbFeCo bilayers, the exchange coupling field in TbFeCo bilayers exhibited less dependence on interfacial roughness than that in IrMn/NiFe bilayers. In addition, by adjusting the composition of TbFeCo, the anisotropy of pinning layer can be manipulated and exhibits strong effects on exchange bias of TbFeCo bilayers. (C) 2003 American Institute of Physics.
High-density MIM capacitors using Al2O3 and AlTiOx dielectrics
(2002-04-01)
Chen, SB
;
Lai, CH
;
Chin, A
;
Hsieh, JC
;
Liu, J
We have investigated the electrical characteristics of Al2O3 and AlTiOx MIM capacitors from IF (100 KHz) to RF (20 GHz) frequency range. Record high capacitance density of 0.5 and 1.0 muF/cm(2) are obtained for Al2O3 and AlTiOx MIM capacitors, respectively, and the fabrication process is compatible to existing VLSI backend integration. However, the AlTiOx MIM capacitor has very large capacitance reduction as increasing frequencies. In contrast, good device integrity has been obtained for Al2O3 MIM capacitor as evidenced from the small frequency dependence, low leakage current, good reliability, small temperature coefficient, and low loss tangent.
Magnetic properties and recording characteristics of high magnetization exchange-coupled double-layer TbFeCo for magnetic flux reading optical recording
(2001-07-01)
Chen, BM
;
Lai, CH
;
Shieh, HPD
;
光電工程學系
;
Department of Photonics
The magnetic properties and recording characteristics of exchange-coupled double-layer (ECDL) disks consisting of a transition metal-rich TbFeCo readout layer with high magnetization and a recording layer were studied for magnetic flux reading optical recording. The effective coercivity of ECDL with rare-earth (recording)/transition metal-rich (readout) films could be greatly enhanced from 1.7 to 7.6kOe through exchange coupling between two active layers. Moreover, ECDL disks possess a lower recording bias field (100 Oe) and a lower onset field (- 150 Oe) for thernioniagnetic writing. The enhanced effective coercivity was explained by the Kobayashi model, and the lower bias field and onset field of ECDL disks were analyzed by the modified nucleation field model. The ECDL disks with magnetization over 300 emu/cm(3), high stability and low recording bias field are potentially applicable for magnetic flux readout toward high density recording at a high writing rate.
Mining the change of events in environmental scanning for decision support
(2004)
Shih, MJ
;
Liu, DR
;
Liau, C
;
Lai, CH
;
資訊管理與財務金融系註：原資管所+財金所
An organization's environment is increasingly complex. Business demand on environmental scanning has significantly increased in recent years due to an attempt to assist management in planning an organization's strategies and responses. The conventional technique for environmental scanning is event detection from text documents such as news stories. Event detection methods recognize events while they neglect to discover the changes of events. This work develops an event change detection (ECD) approach that combines association rule mining and change mining techniques. Detecting changes of events aids managers in making fast responses to the change of external environments. Association rule mining is employed to discover the subject behaviors of events from news stories. Changes of events are identified by comparing the subject behaviors of events from different time periods. The discovered event changes can provide effective decision support for decision makers to capture environmental information in a timely manner and make adequate decisions.
Novel SiO2/AlN/HfAlO/IrO2 memory with fast erase, large triangle V-th and good retention
(2005)
Lai, CH
;
Chin, A
;
Chiang, KC
;
Yoo, WJ
;
Cheng, CF
Using the strong trapping capability of novel AlN (kappa=10), low voltage drop in high-kappa layers and high workfunction IrO2 with low leakage current, the SiO2/AlN/HfAlO(K=17)/IrO2 device shows good 85 degrees C memory integrity of fast 100 is erase, large 3.7V Delta V-th and 1.9V extrapolated memory window for 10-year retention at low 13V program/erase. These increase to 5.5V Delta V-th and 3.4V for 85 degrees C 10-year retention at 1 ms erase.
Positive giant magnetoresistance in ferrimagnetic/Cu/ferrimagnetic films
(2001-06-01)
Lai, CH
;
Lin, CC
;
Chen, BM
;
Shieh, HPD
;
Chang, CR
Spin valves composed of ferrimagnetic/Cu/ferrimagnetic layers were fabricated with the magnetization perpendicular to the film planes. By changing the composition of ferrimagnetic layers, both negative and positive giant magnetoresistance (GMR) can be observed in ferrimagnetic spin valves. For samples consisting of both transition-metal (TM-) rich TbFeCo and GdFeCo, negative GMR values were obtained. Due to the high resistivity of amorphous ferrimagnetic films, the shunting effect of Cu led to relatively small MR ratio. The negative MR effect was 1% for 1.7 nm Cu. For spin valves consisting of rare-earth (RE-)rich TbFeCo and TM-rich GdFeCo, positive GMR values were observed. A thin layer of Co was inserted between RE-rich TbFeCo and Cu to manipulate the sign of GMR. (C) 2001 American Institute of Physics.
Reoxidation behavior of high-nitrogen oxynitride films after O(2) and N(2)O treatment
(2005-05-01)
Lin, BC
;
Chang, KM
;
Lai, CH
;
Hsieh, KY
;
Yao, JM
Reoxidation of a high-nitrogen ultrathin oxynitride (similar to 1.3nm) has been studied. The reoxidation is conducted using an alternation of nitrous oxide and oxygen gas in rapid thermal oxidation (RTO). The new finding in this study is the zig-zag characteristic of the oxidation rate by O(2) and N(2)O. It is clear that the N(2)O oxidation rate is almost independent of the concentration of nitrogen in oxynitride through out the rapid thermal oxidation process, but the O2 oxidation rate is not.
Reoxidation behavior of high-nitrogen oxynitride films after O-2 and N2O treatment
(2005-05-01)
Lin, BC
;
Chang, KM
;
Lai, CH
;
Hsieh, KY
;
Yao, JM
Reoxidation of a high-nitrogen ultrathin oxynitride (similar to 1.3nm) has been studied. The reoxidation is conducted using an alternation of nitrous oxide and oxygen gas in rapid thermal oxidation (RTO). The new finding in this study is the zig-zag characteristic of the oxidation rate by O-2 and N2O. It is clear that the N2O oxidation rate is almost independent of the concentration of nitrogen in oxynitride through out the rapid thermal oxidation process, but the O2 oxidation rate is not.
RF MIM capacitors using high-K Al2O3 and AlTiOx dielectrics
(2002)
Chen, SB
;
Lai, CH
;
Chin, A
;
Hsieh, JC
;
Liu, J
Record high capacitance density of 0.5 and 1.0 muF/cm(2) are obtained for Al2O3 and AlTiOx MIM capacitors respectively, with loss tangent < 0.01 and process compatible to existing VLSI back-end integration. However, the AlTiOx MINI capacitor has large capacitance reduction as increasing frequencies. In contrast, the Al2O3 MINI capacitor has good device integrity of low leakage current of 4.3x10(-8) A/cm(2), small frequency-dependent capacitance reduction, and good reliability.
RF noise in 0.18-mu m and 0.13-mu m MOSFETs
(2002-12-01)
Huang, CH
;
Lai, CH
;
Hsieh, JC
;
Liu, J
;
Chin, A
We have studied the gate finger number and gate ength dependence on minimum noise figure (NFmin) in deep submicrometer MOSFETs. A lowest NFmin. of 0.93 dB is measured in 0.18-mum MOSFET at 5.8 GHz as increasing finger number to 50 fingers, but increases abnormally when above 50. The scaling gate length to 0.13 mum shows larger NFmin than the 0.18-mum case at the same finger number. From the analysis of a well-calibrated device model, the abnormal finger number dependence is due to the combined effect of reducing gate resistance and increasing substrate loss as increasing finger number. The scaling to 0.13-mum MOSFET gives higher NFmin due to the higher gate resistance and a modified T-gate structure proposed to optimize the NFmin for further scaling down of the MOSFET.
Robust ultrathin oxynitride with high nitrogen diffusion barrier near its surface formed by NH3 nitridation of chemical oxide and reoxidation with O-2
(2006-06-01)
Lai, CH
;
Lin, BC
;
Chang, KM
;
Hsieh, KY
;
Lai, YL
We have proposed an approach for growing robust ultrathin oxynitride using conventional thermal processes with the capability of preventing boron penetration. In this method, we obtain oxynitride with high nitrogen concentration (approximate to 13 at. %) on the top and low interface state density (D-it = 2 x 10(10) cm(-2) eV(-1)). The films demonstrate excellent properties in terms of low Dit, low leakage current, high endurance in stressing and superior boron diffusion blocking behavior. This method does not involve any additional capital equipment [such as decoupled plasma nitridation (DPN) or remote plasma nitridation (RPN)] or gas (NO or N2O). In addition, it obtains high-quality oxynitride film with low thermal budget. Most importantly, this process is simple and fully compatible with current process technology. It would be important and interesting for process engineers engaged in the field of gate dielectrics. It is suitable for the next generation of ULSI technology.
Thickness dependence of Co anisotropy in TbFe/Co exchange-coupled bilayers
(2004-06-01)
Lin, CC
;
Lai, CH
;
Wei, DH
;
Hsu, YJ
;
Shieh, HPD
The orientation of element-specific moments was determined by using x-ray magnetic circular dichroism spectroscopy to explore exchange anisotropy of TbFe/Co bilayers. Perpendicular anisotropy of 15 Angstrom Co was induced by TbFe through exchange coupling, resulting in the out-of-plane Co moments. With increasing the thickness, Co moments were gradually tilted to the in-plane orientation because of increasing planar anisotropy. In the bilayer with thick Co, interfacial Fe moments were unidirectionally aligned in the plane, leading to in-plane exchange bias of Co. The coercivity and exchange bias field of Co in the bilayers exhibited a strong dependence on Co thickness. (C) 2004 American Institute of Physics.
Very high density RF MIM capacitor compatible with VLSI
(2005)
Chiang, KC
;
Lai, CH
;
Chin, A
;
Kao, HL
;
McAlister, SP
We have fabricated RF MIM capacitors, using high-kappa TiTAO as the dielectric, which show a record high density of 20 fF/mu m(2). In addition, the capacitors display a small capacitance reduction of only 3.6% over the 100 kHz to 20 GHz range, a low leakage current of 8 pA and a high Q of 120. This was for a typical large 8 pF TiTaO MINI capacitor. The small voltage dependence of the capacitance (Delta C/C) of 770 ppm at 2 GHz, shows that these MIM capacitors are useful for high-precision RF circuits.