Browsing by Author "LEE, CP"

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2-COLOR INFRARED PHOTODETECTOR USING GAAS/ALGAAS AND STRAINED INGAAS/ALGAAS MULTIQUANTUM WELLS
(1993-06-28)
TSAI, KL
;
CHANG, KH
;
LEE, CP
;
HUANG, KF
;
TSANG, JS
A two-color infrared detector using GaAs/A]GaAs and strained InGaAs/AlGaAs multiquantum wells is demonstrated. The response peak of the GaAs/AlGaAs quantum well is at 8 mum, and that of the InGaAs/AlGaAs quantum well is at 5.3 mum. The responsivity of the detector is 1 A/W at 8 mum and 0.27 A/W at 5.3 mum; these are the best values reported for a two-color quantum well infrared detectors (QWIPs) with peak sensitivities in the spectral regions of 3-5.3 mum and 7.5-14 mum. Single-colored 5.3 and 8 mum QWIPs were also fabricated to study the bias dependent behavior. This behavior can be explained using the concept of current continuity. Because of a higher electrical resistance, a high electric field domain is always formed first in the shorter wavelength quantum well stack.
2-COLOR QUANTUM-WELL INFRARED PHOTODETECTOR WITH PEAK SENSITIVITIES AT 3.9 MU-M AND 8.1 MU-M
(1994-08-04)
TSAI, KL
;
LEE, CP
;
TSANG, JS
;
CHEN, HR
;
電子工程學系及電子研究所
A two-colour infra-red photodetector using multistacks of GaAs/AlGaAs quantum wells is demonstrated. The response peaks are at 3.9 and 8.1 mum. The peak responsivities of the detector are 0.4A/W and 35mA/W for 8.1mum and 3.9mum bands, respectively. The detectivities of the 3.9 and 8.1 mum bands are 7.5 x 10(9) and 1.5 x 10(10)cmHz1/2/W. These values are the best reported results for two-colour detectors with peak sensitivities in the spectral regions of 3-5 and 8-12mum.
2-DIMENSIONAL BI-PERIODIC GRATING-COUPLED ONE-COLOR AND 2-COLOR QUANTUM-WELL INFRARED PHOTODETECTORS
(1995-02-01)
TSAI, KL
;
LEE, CP
;
TSANG, JS
;
CHEN, HR
;
CHANG, KH
Multiple quantum well infrared photodetectors (QWIP's) with two-dimensional bi-periodic grating couplers have been demonstrated. For one-color QWIP's, the response linewidths of such QWIP's are found to be much wider than those of conventional grating coupled QWIP's. The bi-periodic gratings have also been applied to two color QWIP's to separately optimize the absorption at two wavelength bands. The large difference in responsivities at the two wavelength bands for devices with single period gratings can be greatly reduced with the use of bi-periodic gratings.
2-DIMENSIONAL SIMULATION OF ORIENTATION EFFECTS IN SELF-ALIGNED GAAS-MESFETS
(1990-10-01)
LO, SH
;
LEE, CP
;
交大名義發表
;
電控工程研究所
;
National Chiao Tung University
2-DIMENSIONAL SIMULATION OF THE DRAIN-CURRENT TRANSIENT EFFECT IN GAAS-MESFETS
(1991-04-01)
LO, SH
;
LEE, CP
;
交大名義發表
;
電控工程研究所
;
National Chiao Tung University
A two-dimensional numerical analysis of the drain-current transient behavior of ion-implantation GaAs MESFETs on undoped semi-insulating substrates is presented. It is found that the EL2 traps with slow transient behaviors play an important role in the drain lag effects. Also, the current overshoot and undershoot can be explained by the capture and the emission of electrons through the EL2 traps, respectively.
A NOVEL TECHNIQUE FOR LOW-THRESHOLD AND HIGH-POWER INGAAS/GAAS STRAINED-LAYER 0.98-MU-M BURIED HETEROSTRUCTURE LASER FABRICATION
(1992-02-01)
LIOU, DC
;
CHIANG, WH
;
LEE, CP
;
CHANG, KH
;
LIU, DG
A novel fabrication technique has been developed for InGaAs/GaAs strained-layer buried heterostructure lasers. Dielectric masks and Zn diffusion are not required in this technique. This novel fabrication process is much easier than the conventional approach and yields excellent laser results. A low threshold of 3 mA and high-power operation for lasing wavelength of 9800 +/- 20 angstrom have been achieved with graded index separate confinement heterostructure devices using this novel technique.
ALGAAS/GAAS HETEROJUNCTION BIPOLAR-TRANSISTORS ON SI SUBSTRATE USING EPITAXIAL LIFT-OFF
(1995-09-01)
FAN, JC
;
LEE, CP
;
HWANG, JA
;
HWANG, JH
;
電子工程學系及電子研究所
Epitaxial lift-off (ELO) technique was used for the first time to transplant AlGaAs/GaAs Heterojunction Bipolar Transistors (HBT's) to Si substrates. Both preprocessed (devices processed before transplantation) and postprocessed (devices processed after transplantation) ELO HBT's On Si were demonstrated in this study. The characteristics of those HBT's on Si with either technique show nearly identical characteristics of the HBT's on GaAs without transplantation, indicating the film quality is maintained after transplantation. Devices with a high current gain of 550 were transplanted without any degradation, and the current gain is not limited by the ELO process. This current gain value is the highest reported for GaAs HBT's on Si with any techniques.
ALGAAS/GAAS HETEROJUNCTION BIPOLAR-TRANSISTORS ON SI SUBSTRATE USING EPITAXIAL LIFT-OFF
(1995-09-01)
FAN, JC
;
LEE, CP
;
HWANG, JA
;
HWANG, JH
;
電子工程學系及電子研究所
Epitaxial lift-off (ELO) technique was used for the first time to transplant AlGaAs/GaAs Heterojunction Bipolar Transistors (HBT's) to Si substrates. Both preprocessed (devices processed before transplantation) and postprocessed (devices processed after transplantation) ELO HBT's On Si were demonstrated in this study. The characteristics of those HBT's on Si with either technique show nearly identical characteristics of the HBT's on GaAs without transplantation, indicating the film quality is maintained after transplantation. Devices with a high current gain of 550 were transplanted without any degradation, and the current gain is not limited by the ELO process. This current gain value is the highest reported for GaAs HBT's on Si with any techniques.
AN ELECTRICAL METHOD TO CHARACTERIZE THERMAL-REACTIONS OF PD/GAAS AND NI/GAAS CONTACTS
(1995-06-01)
CHUANG, HF
;
LEE, CP
;
LIU, DC
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Capacitance-voltage (C-V) and current-voltage (I-V) measurements were used to study the thermal reaction of Pd/GaAs contacts and Ni/GaAs contacts. The thickness of GaAs consumed by the metal/GaAs reaction during annealing was calculated from C-V analyses and I-V analyses. For annealing temperatures below 350 degrees C, the Schottky characteristics of the diodes were good but the electrical junction moves into the GaAs after annealing. The amount of junction movement was calculated directly from our measurements. The diffusion coefficients of Pd and Ni in GaAs at 300 degrees C were estimated both to be around 1.2 x 10(-14) cm(2)/s.
ANALYSIS OF SEVERAL HIGH-ELECTRON-MOBILITY-TRANSISTOR STRUCTURES BY A SELF-CONSISTENT METHOD
(1991-03-01)
LIU, DG
;
CHIN, TC
;
LEE, CP
;
HWANG, HL
;
電控工程研究所
Three HEMT structures, the single heterostructure HEMT (SH-HEMT), the quantum well HEMT (QW-HEMT) and the delta-doped HEMT (delta-HEMT) were analyzed by solving the Schroedinger equation and Poisson equation self-consistently. The potential and the carrier distributions as well as the charge controlled by gate bias were calculated for different structural parameters. Parallel conduction in AlGaAs, which is severe for SH-HEMTs, is greatly reduced in QW-HEMT and delta-HEMT structures. The effect of layer parameters such as spacer layer thickness and quantum-well width on device performance has been studied. SH-HEMT and QW-HEMT have been fabricated for the confirmation of our analysis.
ANALYSIS OF SURFACE-STATE EFFECT ON GATE LAG PHENOMENA IN GAAS-MESFETS
(1994-09-01)
LO, SH
;
LEE, CP
;
電控工程研究所
;
Institute of Electrical and Control Engineering
A two-dimensional transient simulation of the gate lag phenomenon in GaAs MESFET's has been performed. Our results show that the charge exchanges in the population of the surface states at the ungated access region of FET's are responsible for this slow transient phenomenon. The measured ''hole-trap-like'' DLTS signal is directly related to the re-emission of the holes, trapped during the filling pulse. Higher gate pulse can cause more serious lag phenomenon due to larger modulation of surface charge density. Devices with shorter N+-gate spacing and lower surface state densities are shown to have less gate lag effect.
ASYMMETRIC DARK CURRENT IN QUANTUM-WELL INFRARED PHOTODETECTORS
(1994-05-02)
TSAI, KL
;
LEE, CP
;
CHANG, KH
;
LIU, DC
;
CHEN, HR
Asymmetric dark current versus voltage characteristics in quantum weil infrared photodetectors have been studied. A model based on asymmetrical potential barriers was proposed. The asymmetrical potential barriers, which are most likely due to the accumulation of oxygen impurities at one of the interfaces, cause the asymmetrical I-V characteristics. The height of the potential spike is found to increase with the Al content in the AlGaAs barriers. Calculations based on our model agree well with experimental results.
BEHAVIOR OF THE 1ST LAYER GROWTH IN GAAS MOLECULAR-BEAM EPITAXY
(1990-10-01)
LIU, DG
;
LEE, CP
;
CHANG, KH
;
WU, JS
;
LIOU, DC
BINDING-ENERGIES OF D- ION IN GAAS QUANTUM-WELL
(1994-04-01)
CHANG, YH
;
YEH, JJ
;
SHEU, YM
;
WANG, CC
;
CHEN, TC
Magnetic field dependent binding energies of the D- ion in the center of a 210 angstrom GaAs quantum well are determined by temperature magneto-transport measurments. The binding energies increase from 2.1 meV at 2T to 4 meV at 8T, and are consistently higher than the transition energies ootained from magneto-optical measurements performed on the same sample. We conclude from these data that in the magneto-optical measurement the observed transitions are between ground and excited D- states.
CHARACTERIZATION OF IMPROVED ALGAAS/GAAS RESONANT TUNNELING HETEROSTRUCTURE BIPOLAR-TRANSISTORS
(1991-02-01)
WU, JS
;
CHANG, CY
;
LEE, CP
;
CHANG, KH
;
LIU, DG
We report on the fabrication of AlGaAs/GaAs resonant tunneling heterostructure bipolar transistors (RTHBT's). The devices exhibit a current peak in the transfer characteristics, with peak-to-valley current ratios of 1.7 and 9 at 300 K and 77 K, respectively. The common-emitter small signal current gains at 300 K and 77 K reach 40 and 28, respectively. They are the best results to date for AlGaAs/GaAs resonant tunneling transistors. Because the double barriers are placed in the emitter and far from the emitter-base interface, and the heterostructure emitter suppresses the hole injection from the base to the emitter, the occurrence of the negative differential resistance (NDR) in the device characteristics is governed by the emitter current but not by the base current. The operation mechanism of the NDR behavior in the common-emitter output characteristics is discussed.
COMPARISON OF AU/NI/GE, AU/PD/GE, AND AU/PT/GE OHMIC CONTACTS TO N-TYPE GAAS
(1990-01-01)
LIN, C
;
LEE, CP
;
電控工程研究所
;
Institute of Electrical and Control Engineering
COMPOSITION MODULATION OF INXGA1-XAS QUANTUM-WELLS BY FAST DIMER ARSENIC FLUX CHANGE USING VALVED ARSENIC CRACKER
(1994-01-01)
LIU, DC
;
LEE, CP
;
TSAI, KL
;
TSANG, JS
;
CHEN, HR
By fast change of the As-2 flux using a high temperature valved cracker, we have demonstrated the growth of strained InxGa1-xAs quantum wells with different compositions. The modulation of composition is due to the change in incorporation rates of the group III atoms under different As-2 fluxes. Photoluminescence (PL) emission from the quantum wells clearly indicates the change in composition. A change of In composition from 20.6% to 8.5%, has been achieved by changing the V/III beam-equivalent-pressure (BEP) ratio from 11.7 to 3.9. By this technique of composition modulation, we have fabricated strained InxGa1-xAs/GaAs single quantum well lasers with different emission wavelengths.
COMPOSITIONAL DEPENDENCE OF THERMAL-STABILITY OF REFRACTORY-METAL SILICIDE SCHOTTKY CONTACTS TO GAAS
(1989-09-01)
LEE, CP
;
LIU, TH
;
WU, SC
;
奈米中心
;
Nano Facility Center
COMPOSITIONAL DISORDERING OF ALGAAS/GAAS SUPERLATTICES BY USING THE LOW-TEMPERATURE-GROWN GAAS
(1995-07-01)
TSANG, JS
;
LEE, CP
;
FAN, JC
;
TSAI, KL
;
CHEN, HR
The use of low-temperature (similar to 200 degrees C) grown GaAs by molecular beam epitaxy to induce compositional disordering of AlGaAs/GaAs superlattices has been studied. After furnace annealing between 700 and 850 degrees C for 30 min, an obvious blue shift in the peak wavelength of the superlattice emission is observed by the 77 K photoluminescence (PL), indicating that the emission has been changed from that of the GaAs quantum wells to that of the intermixed AlGaAs. The PL shift and the depth profile of Al concentration measured by secondary ion mass spectrometry indicate that the superlattice is nearly totally disordered after 850 degrees C annealing. (C) 1995 American Vacuum Society.
CURRENT GAINS OF ALAS/GAAS TUNNELING EMITTER BIPOLAR-TRANSISTORS WITH 25-500-ANGSTROM BARRIER THICKNESS
(1993-10-14)
CHEN, HR
;
LEE, CP
;
CHANG, CY
;
TSAI, KL
;
TSANG, JS
The current gain of an AlAs/GaS tunnelling emitter bipolar transistor (TEBT) is found to increase monotonically with barrier thickness in the range 25-200 angstrom and fall off for barrier thickness increasing from 200 to 500 angstrom. It is found that a thicker barrier can suppress the base-to-emitter hole injection better and increase the current gain, but a barrier which is too thick decreases the current gain due to the suppression of the electron current.