Browsing by Author "CHEN, JF"

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DOPING AND TEMPERATURE DEPENDENCES OF MINORITY-CARRIER DIFFUSION LENGTH AND LIFETIME DEDUCED FROM THE SPECTRAL RESPONSE MEASUREMENTS OF P-N-JUNCTION SOLAR-CELLS
(1982)
WU, CY
;
CHEN, JF
;
交大名義發表
;
電控工程研究所
;
National Chiao Tung University
EFFECTS OF SB4/GA RATIOS ON THE ELECTRICAL-PROPERTIES OF GASB SCHOTTKY DIODES
(1992-03-15)
WANG, YH
;
HOUNG, MP
;
SZE, PW
;
CHEN, JF
;
CHO, AY
Au, Cu, Ag, and Al are deposited on Te-doped n-GaSb layers directly grown on lattice mismatched GaAs semi-insulating substrates. Sb4/Ga beam equivalent pressure ratios are found to profoundly influence the electrical properties of the Schottky diodes investigated here. The fact that both breakdown voltage and barrier height decrease with increasing Sb4/Ga ratios is attributed to the increase in surface state densities for samples grown at higher Sb4/Ga ratios. This suggestion is further confirmed by the model of surface state densities employing the relationship of barrier height to metal work function. The surface state densities are in the range of 2.3 x 10(14) to 1.2 x 10(15) states/cm2/eV corresponding to Sb4/Ga ratios of 2 to 9, respectively. X-ray rocking peaks of samples grown at various Sb4/Ga ratios, and subsequently subjected to annealing, indicate different interactions at the interfaces which might support the observations.
ELECTRICAL AND MICROSTRUCTURAL CHARACTERISTICS OF TI CONTACTS ON (001)SI
(1993-08-15)
LIAUH, HR
;
CHEN, MC
;
CHEN, JF
;
CHEN, LJ
;
電子工程學系及電子研究所
An investigation of the electrical and microstructural characteristics of the Ti contact on silicon has been carried out. The presence of As in Ti/n+-Si samples was found to retard the formation of polycrystalline silicide (p-silicide) compared with that in Ti/p+-Si samples with BF2+ implantation. Amorphous interlayers (a-interlayers) were found to be present in both Ti/n-Si and Ti/p-Si samples annealed at temperatures of and lower than 450-degrees-C. Although the Schottky barrier heights (SBH's) vary for about 0.05-0.08 eV for samples annealed over a temperature range from room temperature to 900-degrees-C, SBH's at the a-interlayer/n-Si and a-interlayer/p-Si were measured to be about 0.52-0.54 and 0.59-0.57 eV, respectively. The specific contact resistance (p(c)) in the Ti/n+-Si system was measured to be the lowest with a value of 1.4 X 10(-7) OMEGA cm2 when the a interlayer is present. In Ti/p+-Si system, the minimum rho(c) is about 3 X 10(-7) OMEGA cm2. The variation in contact resistance with annealing temperature for both Ti/n+-Si and Ti/p+-Si samples is correlated to the change in dopant concentration beneath the contacts as well as microstructures. In the temperature regime where the a interlayer is in contact with the silicon substrate, the junction diode leakage current densities (J(leak's)) are considerably lower than those in samples annealed at higher temperatures. The J(leak) at - 6 V reverse bias is lower than 1 nA/cm2. The breakdown voltage is about 14 V (16 V) for the n+/p (p+/n) junction. The thickness of consumed Si is less in samples annealed at low temperature, and the a-interlayer/Si or p-silicide/Si interface is accordingly farther away from the junction as well as the end-of-range defects. The interface of p-silicide/Si is rougher than that of a-interlayer/Si. In addition, the roughness of the p-silicide/Si interface increases with annealing temperature. For both p+/n and n+/p junctions annealed at 900-degrees-C, rough p-silicide/Si interfaces are thought to lead to spiking and increase the leakage currents.
ELECTRICAL-PROPERTIES OF UNDOPED AND SNTE-DOPED GAXIN1-XSB MOLECULAR-BEAM-EPITAXIALLY GROWN ON GAAS
(1995-01-01)
CHEN, JF
;
JAW, SH
;
CHO, AY
;
電子物理學系
;
Department of Electrophysics
Electrical properties of undoped and SnTe-doped GaxIn1-xSb on GaAs grown by molecular beam epitaxy are studied. In the studied composition x from 0.65 to 1, source SnTe is found to be an n-type dopant. The SnTe incorporation efficiency in GaxIn1-xSb is found to have no significant difference from SnTe in GaSb. The fitted ionized impurity concentrations for GaSb increases proportionally with the sample's donor concentrations, suggesting that the charged impurities are introduced through SnTe doping. On the other hand, for GaxIn1-xSb, the fitted ionized impurity concentrations do not vary with the total donor concentration. This suggests that material inhomogeneities or imperfections in GaxIn1-xSb may be the cause of mobility values which are lower than expected. In addition, the V/III beam equivalent pressure (BEP) ratio is found to critically influence the quality of the SnTe-doped ternary layers.
INTERBAND TUNNELING BETWEEN VALENCE-BAND AND CONDUCTION-BAND QUANTUM-WELLS IN A GASB/ALSB/INAS/ALSB/GASB/ALSB/INAS TRIPLE-BARRIER STRUCTURE
(1992-08-01)
CHEN, JF
;
CHO, AY
;
電子物理學系
;
Department of Electrophysics
We report on the experimental studies of an interband tunneling effect between GaSb valence-band and InAs conduction-band quantum wells in a GaSb/AlSb/InAs/AlSb/GaSb/AlSb/InAs triple-barrier interband tunneling device. Multiple negative differential resistances were observed both at room temperature and 77 K. By varying the InAs well width to adjust the alignment of the conduction-band and the valence-band quasi-bound states, we observed more than one order of magnitude variation in the peak current density, indicating a significant quantization effect. Possible current conduction mechanisms were discussed based on the dependence of the peak-current density on the InAs well width.
INTERFACIAL REACTIONS OF TITANIUM THIN-FILMS ON ION-IMPLANTED (001) SI
(1993-04-01)
LIAUH, HR
;
CHEN, MC
;
CHEN, JF
;
CHEN, LJ
;
LUR, W
An investigation on the influences of doping impurities on the formation of titanium silicide has been carried out. The formation of polycrystalline silicide was observed to be retarded by the presence of As in Ti/As+-Si samples compared with those in Ti/BF2+-Si samples. Superior thermal stability of TiSi2 was found to occur in BF2+ implanted samples than that in blank and As+ implanted samples. The resistance to island formation in BF2+ implanted samples is attributed to the retardation of grain growth by the segregation of fluorine atoms at the grain boundaries.
INVESTIGATION OF NEGATIVE DIFFERENTIAL RESISTANCE PHENOMENA IN GASB/ALSB/INAS/GASB/ALSB/INAS STRUCTURES
(1994-10-01)
WANG, YH
;
LIU, MH
;
HOUNG, MP
;
CHEN, JF
;
CHO, AY
The negative differential resistance (NDR) phenomena were observed in GaSb/AlSb/InAs/-GaSb/AlSb/InAs resonant interband tunnel structures. Electron has resonantly achieved interband tunneling through the InAs/GaSb broken-gap quantum well. The InAs well width causes significant variations of the peak current density and NDR behaviors. The peak current density varies exponentially with the AlSb barrier thickness. The multiple NDR behavior was observed with appropriate InAs well and AlSb barrier thickness, e.g., 30 angstrom thick AlSb barrier and 240 angstrom wide InAs well. Only single negative resistance has, otherwise, been seen. The three-band model was used to interpret the effect of the InAs well and AlSb barrier on the current-voltage characteristics of GaSb/AlSb/InAs/GaSb/AlSb/InAs structures.
MOLECULAR-BEAM EPITAXY GROWTH OF INAS-ALSB-GASB INTERBAND TUNNELING DIODES
(1993-03-01)
CHEN, JF
;
CHO, AY
;
電子物理學系
;
Department of Electrophysics
This paper presents our studies of the growth of InAs/GaAs and GaSb/GaAs heterojunctions by molecular beam epitaxy and their applications in fabricating the InAs-AlSb-GaSb interband tunneling devices. The Hall effect and x-ray diffraction were used to determine the optimum growth conditions for the layers. In addition, the qualities of the InAs and GaSb epilayers, grown under their optimum conditions, were compared. The full width at half maximum (FWHM) from the x-ray diffraction for a GaSb epilayer is about 50 arcsec narrower than an InAs epilayer of the same thickness. The narrower FWHM and excellent surface morphology of the GaSb layer have led us to grow the polytype heterostructure on a p+-GaAs substrate using a p+-GaSb as the buffer layer. The polytype tunneling structures grown on GaAs substrates under these conditions show good negative differential resistance properties. Five different interband tunneling structures are compared and discussed in terms of their peak-current densities and peak-to-valley current ratios.
SCHOTTKY-BARRIER HEIGHTS OF THE AMORPHOUS INTERLAYER SI INTERFACES IN TITANIUM THIN-FILMS ON (001)SI
(1992-11-02)
LIAUH, HR
;
CHEN, MC
;
CHEN, JF
;
CHEN, LJ
;
電子工程學系及電子研究所
Schottky barrier heights (SBHs) of amorphous interlayer/Si interfaces in Ti thin films on (001)Si have been measured by forward current-voltage technique. A-interlayers were observed to form by cross-sectional transmission electron microscopy in both Ti thin films on n- and p-type silicon systems in samples annealed at temperatures of and lower than 450-degrees-C for 30 s. Although the SBHs vary for about 0.05-0.08 eV for samples annealed over a temperature range from room temperature to 900-degrees-C, SBHs at the a-interlayer/n-Si and a-interlayer/p-Si were measured to be 0.52-0.54 and 0.59-0.57 eV, respectively. Formation of homogeneous metal a-interlayer/Si interfaces correlated with their SBHs in a number of refractory metal-silicon systems promises to greatly clarify the SBH formation mechanisms.
SUPPRESSION OF THE BORON PENETRATION INDUCED SI/SIO2 INTERFACE DEGRADATION BY USING A STACKED-AMORPHOUS-SILICON FILM AS THE GATE STRUCTURE FOR PMOSFET
(1994-05-01)
WU, SL
;
LEE, CL
;
LEI, TF
;
CHEN, JF
;
CHEN, LJ
This letter reports that the boron penetration through the thin gate oxide into the Si substrate does not only cause a large threshold voltage shift but also induces a large degradation in the Si/SiO2 interface. An atomically flat Si/SiO2 interface can be easily obtained by using a stacked-amorphous-silicon (SAS) film as the gate structure for p+ poly-Si gate MOS devices even the annealing temperature is as high as 1000-degrees-C.
TEMPERATURE COEFFICIENTS OF THE OPEN-CIRCUIT VOLTAGE OF P-N-JUNCTION SOLAR-CELLS
(1982)
WU, CY
;
CHEN, JF
;
交大名義發表
;
電控工程研究所
;
National Chiao Tung University
THE EFFECTS OF GASB/INAS BROKEN GAP ON INTERBAND TUNNELING CURRENT OF A GASB/INAS/GASB/ALSB/INAS TUNNELING STRUCTURE
(1992-05-01)
CHEN, JF
;
CHO, AY
;
電子物理學系
;
Department of Electrophysics
We propose and study a new GaSb/InAs/GaSb/AlSb/InAs broken-gap interband tunneling diode by varying the thicknesses of the InAs layer. A twice-higher peak current density and a three-times-higher peak-to-valley current ratio in the proposed structure with a 30-angstrom-thick InAs layer were observed relative to the structure with no InAs layer. This result indicates that the characteristic of the negative differential resistance can be improved simply by placing a thin effective InAs barrier on the GaSb side of the GaSb/AlSb/InAs single-barrier structure. The increase of the peak current is interpreted as the result of forming a quasi-bound state in the GaSb well. This interpretation is supported by the observation that the current-voltage characteristic of the proposed structure is similar to that of a conventional GaSb/AlSb/GaSb/AlSb/InAs double-barrier interband tunneling structure.