Browsing by Author "LIN, KC"

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A PSEUDOMORPHIC GAINP/INP MESFET WITH IMPROVED DEVICE PERFORMANCE
(1993-12-01)
LIN, KC
;
HSIN, YM
;
CHANG, CY
;
CHANG, EY
;
材料科學與工程學系
A high band-gap GaInP epitaxial material was grown on InP to increase the Schottky barrier height of the InP MESFET. The Schottky gate materials used in this study were Au and Pt,Si. The pseudomorphic GaInP/InP MESFET with Au gate has a Schottky barrier height of 0.54 eV and the reverse leakage current of the device is 10(-2) times lower than the conventional InP MESFET. The extrinsic and intrinsic transconductance of the pseudomorphic MESFET were 66.7 and 104.2 mS/mm respectively for the 5 mu m gate length GaInP/InP MESFET.
ANOMALOUS MOBILITY ENHANCEMENT IN HEAVILY CARBON-DOPED GAAS
(1994-05-15)
CHEN, HD
;
FENG, MS
;
LIN, KC
;
CHEN, PA
;
WU, CC
An anomalous mobility enhancement and metallic-type conductivity were observed in heavily carbon-doped GaAs grown by low-pressure metalorganic chemical vapor deposition. The 77 K mobility was slightly lower than that of 300 K for hole concentration between 1 x 10(18) and 4 x 10(18) cm-3. However, the 77 K mobility was enhanced from p > 4 X 10(18) cm-3, and the 300 K mobility slowly decreased with increasing hole concentration that ranged from 7 X 10(18) to 3 X 10(19) cm -3. As a result, the 77 K mobility was around 50%-60% greater than the 300 K mobility due to the metallic-type conductivity.
BACK-GATING EFFECTS ON THE GA0.1IN0.8P/INP/INGAAS HIGH-ELECTRON-MOBILITY TRANSISTOR
(1995-07-01)
LIN, KC
;
CHANG, CY
;
WU, CC
;
CHEN, HD
;
CHEN, PA
Pseudomorphic GaInP/InP/InGaAs high electron mobility transistors (HEMT) with improved Schottky contacts and excellent electrical characteristics are grown by low-pressure metal-organic chemical vapor deposition (LP-MOCVD) on the InP substrate. These HEMTs with 1.71 mu m gate length have an average extrinsic transconductance of 225 mS/mm. The back-gating effects of this device structure are investigated for the first time in this structure. Both positive and negative bias are applied to the ohmic and Schottky back-gate contacts of these devices. The positive back-gate bias has no effect on the drain current or the output transconductances of these devices. The effect of the negative back-gate bias is very similar to that when negative bias is applied on the gate of these HEMTs.
CARBON INCORPORATION DURING GROWTH OF GAAS BY TEGA-ASH3 BASE LOW-PRESSURE METALORGANIC CHEMICAL-VAPOR-DEPOSITION
(1993-06-01)
CHEN, HD
;
CHANG, CY
;
LIN, KC
;
CHAN, SH
;
FENG, MS
Heavily carbon-doped GaAs (1 X 10(18) approximately 1 X 10(20) cm-3) grown by low-pressure metalorganic chemical vapor deposition using triethylgallium and arsine as sources and liquid carbon-tetrachloride (CCl4) as dopant has been investigated. The carrier concentration was verified at various growth temperatures, V/III ratios, and CC]4 flow rates. Dopant concentration first increased from 550-degrees-C and reached a maximum at 570-degrees-C growth temperature (T(g)) and then decreased monotonously. Carbon incorporation was strongly enhanced when the V/III ratio was less than 30 at T(g) = 590-degrees-C or less than 40 at T(g) = 630-degrees-C. Hole concentration increased and then decreased as CCl4 flow rate increased. Growth rate of layers decreased as growth temperature and flow rate Of CCl4 increased. The doping efficiency of epitaxial layers grown on the (100) substrate was higher than that on the 2-degrees off toward [110] misoriented substrate. Carbon-doped GaAs films had higher Hall mobility than zinc-doped GaAs films at high doping levels due to less self-compensation. The highest dopant concentration in this system was 2.3 X 10(20) cm-3 at T(g) = 580-degrees-C and V/III = 10.
CATION SOURCE DEPENDENCE OF GA0.5IN0.5P GROWTH-RATE BY LOW-PRESSURE METALORGANIC CHEMICAL-VAPOR-DEPOSITION
(1994-06-15)
WU, JW
;
CHANG, CY
;
LIN, KC
;
CHAN, SH
;
CHEN, HD
The Ga0.5In0.5P epilayer was grown by low-pressure metalorganic chemical vapor deposition. Trimethylgallium and triethylgallium were used as the gallium source's, while trimethylindium and ethyldimethylindium were used as the indium sources. The use of triethylgallium incorporated with trimethylindium enhanced the growth rate of Ga0.5In0.5P as compared to incorporation with ethyldimethylindium. While the use of trimethylgallium incorporated with ethyldimethylindium enhanced the growth rate of Ga0.5In0.5P significantly, as compared to incorporation with trimethylindium.
DOPING OF INGAP EPITAXIAL LAYERS GROWN BY LOW-PRESSURE METAL-ORGANIC CHEMICAL-VAPOR-DEPOSITION
(1993-06-20)
WU, CC
;
LIN, KC
;
CHAN, SH
;
FENG, MS
;
CHANG, CY
DEZn and H2Se were utilized as p- and n-type dopant sources for the growth in InGaP layers by low pressure metal-organic chemical vapor deposition (LP-MOCVD). The decrease in intensity of the extra spots of electron diffraction indicates that disordering is induced by the zinc doping. Streaky and wavy diffraction patterns demonstrate the formation of anti-phase domains caused by the Se dopant incorporation. The growth rate of the grown layer is reduced by more than 10% owing to the dopant incorporation. A photoluminescence emission energy difference of 141 meV between undoped and Zn-doped (5.8 x 10(18) cm-3) InGaP was obtained. The effects of doping on disordering, degeneracy of quasi-Fermi level and lattice constant reduction of grown layers were included in this study.
IN0.49GA0.51P/GAAS HETEROSTRUCTURES GROWN BY LOW-PRESSURE METALORGANIC CHEMICAL-VAPOR-DEPOSITION
(1993-07-01)
FENG, MS
;
LIN, KC
;
WU, CC
;
CHEN, HD
;
SHANG, YC
We have successfully grown In0.49Ga0.51P/GaAs heterostructures and made InGaP-based high electron mobility transistors (HEMTs) by low-pressure metalorganic chemical vapor deposition. We have found the epitaxial layer of InGaP with a Hall mobility of 4073 cm2/V s (300 K) and the photoluminescence full width at half-maximum of 1 meV (4.2 K) for GaAs, 12 meV (4.2 K) for In0.49Ga0.51P. Zinc-induced disordering phenomenon was examined by transmission electron microscope. By Shubnikov-de Haas measurement, we demonstrated the existence of a two-dimensional electron gas in InGaP/GaAs heterojunctions. The sheet carrier concentration of 2DEG is around 8.8 X 10(11) cm-2 at 1.5 K. A HEMT device with 1 mum X 40 mum gate (pattern) shows an extrinsic transconductance of 65.5 mS/mm and an intrinsic transconductance of 266 mS/mm at 300 K.
LOW-TEMPERATURE LUMINESCENT PROPERTIES OF DEGENERATE P-TYPE GAAS GROWN BY LOW-PRESSURE METALORGANIC CHEMICAL-VAPOR-DEPOSITION
(1994-02-15)
CHEN, HD
;
FENG, MS
;
CHEN, PA
;
LIN, KC
;
WU, CC
Low-temperature (20 K) luminescent properties of heavily carbon- and zinc-doped GaAs grown by low-pressure metalorganic chemical vapor deposition were investigated. The luminescence linewidth became broader at low temperatures when p > 4 X 10(19) cm-3 due to the appearance of a shoulder peak. The main peak shifted to low energy when the dopant concentration was increased; however, the shoulder peak was at around 1.485 eV and was nearly independent of the dopant concentration. The peak of the band-to-acceptor transition occurred at low temperature and dominated the emission spectra of degenerate GaAs. The peak energy of Zn-doped samples was lower than that of C-doped samples because of the existence of defects. The excitation power intensity was varied to investigate the behavior of the shoulder peak for both types of dopants. The shoulder peak was a part of the main peak because of the recombination between the conduction band and the bottom of the impurity band.
MAGNESIUM DOPING OF INGAALP GROWN BY LOW-PRESSURE METALORGANIC CHEMICAL-VAPOR-DEPOSITION
(1994-09-05)
WU, CC
;
CHANG, CY
;
CHEN, PA
;
CHEN, HD
;
LIN, KC
Bis(cyclopentadienyl) magnesium, CP2Mg, was used as a magnesium dopant in the InGaAlP layers by low-pressure metalorganic chemical vapor deposition. The hazy surface morphology of heavily doped InGaAlP layers is significantly improved by using magnesium dopant instead of the conventional zinc dopant. We demonstrate that the effective doping efficiency of magnesium is two orders of magnitude higher than that of zinc dopant in the heavily doped InGaAlP layer grown at 720-degrees-C.
PASSIVATION OF GAAS POWER FIELD-EFFECT TRANSISTOR USING ELECTRON-CYCLOTRON-RESONANCE CHEMICAL-VAPOR-DEPOSITION SILICON-NITRIDE TECHNIQUE
(1994-12-01)
CHANG, EY
;
LIN, KC
;
WU, JW
;
CHEN, TH
;
CHEN, JS
Monolithic microwave integrated circuit (MMIC) chips are typically passivated with dielectric films to improve their long-term environmental reliability. Improper passivation generally degrades chip performance and reduces wafer yield. This paper reports the change of metal-semiconductor field-effect transistor (MESFET) parameters after silicon nitride passivation using electron cyclotron resonance chemical vapor deposition (ECR-CVD). In general, the changes in the electrical parameters after passivation are small. Gate-drain breakdown voltage of the MESFET's after ECR-CVD passivation is significantly improved compared to that after PECVD. The microwave characteristics of the high-powered MESFET's passivated using ECR-CVD silicon nitride are also reported in this paper.
PHOTOLUMINESCENCE OF HEAVILY P-TYPE-DOPED GAAS - TEMPERATURE AND CONCENTRATION DEPENDENCES
(1994-04-01)
CHEN, HD
;
FENG, MS
;
CHEN, PA
;
LIN, KC
;
WU, JW
Photoluminescent (PL) properties of heavily carbon- and zinc-doped GaAs were investigated for concentration from 8 X 10(17) to 2.3 x 10(20) cm-3 and temperature from 300 K to 20 K. Both a band-to-band (B, B) peak and a band-to-acceptor (e, A) peak appeared at 300 K for the heavily p-type-doped GaAs PL spectra, even in degenerated GaAs. The variation of the intensities of the (e, A) peak and (B, B) peak with concentration and temperature was investigated, and the change in position of the two peaks at various concentrations and temperatures was observed. The rapid increase in linewidth with increasing concentration due to the appearance of a shoulder peak was also studied; this behavior is different from that of the shoulder peak in the PL spectrum from Zn-doped crystal.
REACTIVE ION ETCH OF GAAS AND ALGAAS USING BCL3, SICL4 AND SF6, INSTEAD OF CCL2F2
(1994)
WU, JW
;
CHANG, CY
;
LIN, KC
;
CHANG, EY
;
HWANG, JH
REACTIVE ION ETCHING OF GAINP, GAAS, AND ALGAAS
(1995-04-01)
WU, JW
;
CHANG, CY
;
CHANG, EY
;
CHANG, SH
;
LIN, KC
We have investigated the reactive ion etching of GaInP, GaAs, and AlGaAs. High etching selectivity of GaAs to AlGaAs (or to GaInP) can be achieved due to the formation of aluminum fluoride (AlF3) and indium fluoride (InF3) using a BCl3/SF6 mixture. By using a CH4/H-2 mixture, a polymer film is accumulated on the GaAs surface after reactive ion etching. This polymer film inhibits the reactive ion etching of GaAs. There is no polymer film accumulated on the surface of GaInP. The polymer deposited on the surface of GaInP is removed as the etching products are being removed. Hence, a high etching selectivity of GaInP to GaAs can be achieved by using a CH4/H-2 mixture.
SEMIINSULATING IRON-DOPED INDIUM-PHOSPHIDE GROWN BY LOW-PRESSURE METAL ORGANIC-CHEMICAL VAPOR-DEPOSITION
(1993-03-01)
WU, CC
;
FENG, MS
;
LIN, KC
;
CHAN, SH
;
CHANG, CY
(C5H5)2Fe and Fe(CO)5 were used as the 3d transition-metal dopant sources in the growth of semi-insulating InP epitaxial layers by low-pressure metal-organic chemical vapour deposition (MOCVD). From the bright- and dark-field images of transmission electron microscopy (TEM) analysis, many precipitates were observed. Three extra peaks in the X-ray diffraction pattern were found. The peaks of band-band recombination, donor-acceptor pair recombination transitions and the recombination of donor-acceptor pair with one-phonon emission were observed in the short-wavelength range of low-temperature photoluminescence measurement. Three Fe-related peaks were observed at 0.7079, 0.6897 and 0.6683 eV. For a wide range (10-600) of In/Fe molar fraction, the resistivity remained at high values (about 10(8) OMEGA cm) and the highest resistivity appeared at 5 x 10(8) OMEGA cm for a 1 mum layer with a breakdown voltage of 9 V.
STUDY OF SCHOTTKY CONTACTS ON N-GA0.51IN0.49P BY LOW-PRESSURE METAL-ORGANIC CHEMICAL-VAPOR-DEPOSITION
(1993-11-01)
CHANG, EY
;
LAI, YL
;
LIN, KC
;
CHANG, CY
;
材料科學與工程學系
A comprehensive study of the Schottky contacts on Ga0.51In0.49P has been made. The Ga0.51In0.49P epitaxial layer was successfully grown on the GaAs substrate by low-pressure metal-organic chemical-vapor deposition to form a lattice-matched heterostructure. Three different types of films, including single-layer metal (Pt, Ni, Pd, Au, Co, Mo, W, Cr, Ti, Al, Ta, and In), metal silicides (WSi2, W5Si3 PtSi, and Pt2Si), and TiW nitrides (TiWN(X)) as the Schottky contacts metals on Ga0.51In0.49P were studied. Due to the high-band-gap nature of Ga0.51In0.49P, the Schottky contacts on Ga0.51In0.49P demonstrate good characteristics. The barrier heights range from 0.79 to 1.19 eV depending on the selection of the metals and the annealing conditions. Among single-metal films, Pt film demonstrates the best thermal stability. A barrier height of 1.09 eV and an ideality factor of 1.06 were obtained even after the Pt Schottky diode was furnace annealed at 500-degrees-C for 30 min. For refractory compounds, the TiWN(X) film with the highest nitrogen content shows the best thermal stability with a barrier height of 1.00 eV and an ideality factor of 1.04 even after high-temperature annealing at 850-degrees-C.
SUBMICRON T-SHAPED GATE HEMT FABRICATION USING DEEP-UV LITHOGRAPHY
(1994-08-01)
CHANG, EY
;
LIN, KC
;
LIU, EH
;
CHANG, CY
;
CHEN, TH
A new combination of low/high/low sensitivity trilayer (PMMA/PMIPK/PMMA) resist system was used for deep UV lithography to fabricate submicron T-shaped gate. Gate length as narrow as 0.2 mum is achieved. The GaAs HEMT's with 0.3 mum T-shaped Ti/Pt/Au gate is fabricated using this technology. The HEMT demonstrated a 0.6 dB noise figure and 13 dB associated gain at 10 GHz. This deep UV lithography process provides a high throughput and low cost alternative to E-beam lithography for submicron T-gate fabrication.
THE RELIABILITY OF MULTILEVEL METALLIZATION ON INGAAS/GAAS LAYERS
(1994)
CHANG, EY
;
CHEN, JS
;
WU, JW
;
LIN, KC
;
材料科學與工程學系
THE SELECTIVITY OF REACTIVE ION ETCH OF GA0.51IN0.49P/GAAS
(1994)
WU, JW
;
CHAN, SH
;
LIN, KC
;
CHANG, CY
;
CHANG, EY
THE THERMAL-STABILITY OF OHMIC CONTACT TO N-TYPE INGAAS LAYER
(1995-02-01)
WU, JW
;
CHANG, CY
;
LIN, KC
;
CHANG, EY
;
CHEN, JS
The thermal stability of ohmic contact to n-type InGaAs layer is investigated. When Ni/Ge/Au is used as the contact metal, the characteristics of the ohmic contact are degraded after thermal treatment. The specific contact resistance of (Ni/Ge/Au)-InGaAs ohmic contact after annealing at 450 degrees C is about 15 times larger than that of as-deposited sample. This is due to the decomposition of InGaAs and the interdiffusion of Ga and Au.-A new phase of Au4In appears after annealing at 300 degrees C. While in the case of Ti/Pt/Au, Au does not penetrate into the InGaAs layer as revealed by secondary ion mass spectroscopy. The specific contact resistance of(Ti/Pt/Au)-InGaAs ohmic contact after annealing at 450 degrees C is eight times larger than that of as-deposited sample. Therefore, the thermal stability of(Ti/Pt/Au)-InGaAs ohmic contact is better than that of(Ni/Ge/Au)-InGaAs ohmic contact.
TIWN SCHOTTKY CONTACTS TO N-GA(0.51)IN(0.49)P
(1994-08-01)
LIN, KC
;
CHANG, EY
;
WANG, SP
;
LAI, YL
;
CHANG, CY
The study of the applicability of TiW nitrides (TiWNx) as the Schottky contact metals to the n-type Ga0.51In0.49P has been made. The Ga0.51In0.49P epitaxial layer is successfully grown on the GaAs substrate by low-pressure metalorganic chemical vapor deposition (LP-MOCVD) to form a lattice-matched heterostructure. The RF-magnetron sputtering system is utilized for nitride deposition. Thermal stability of the nitride films is studied with the aid of a rapid thermal annealing system. The material properties are characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and Auger electron spectroscopy (AES). With sufficient nitrogen content, the Schottky contacts showed excellent electrical and physical characteristics even after a high-temperature annealing. The barrier heights, ranging from 0.81 to 1.05 eV, depend on the content of nitrogen and the rapid thermal annealing (RTA) annealing condition. The XRD and AES results indicate no interaction occurring at the TiWNx/GaInP interface of both as-deposited and annealed samples. The outstanding characteristics of the Schottky contact are attributed to the high band-gap nature of the GaInP and the incorporation of nitrogen into the TiW films.