Browsing by Author "CHANG, EY"

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A PSEUDOMORPHIC GAINP/INP MESFET WITH IMPROVED DEVICE PERFORMANCE
(1993-12-01)
LIN, KC
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HSIN, YM
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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.
AN ULTRA-LOW COST AND MINIATURE 950-2050 MHZ GAAS MMIC DOWNCONVERTER .1. DESIGN APPROACH AND SIMULATION
(1995-05-01)
HSIEH, TH
;
WANG, H
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WANG, TH
;
CHEN, TH
;
CHIANG, YC
A miniature ultra low cost 950-2050 MHz GaAs MMIC downconverter has been designed for satellite TV application using a 1-mu m gate-length, ion-implanted GaAs MESFET foundry process. To accurately predict circuit performances, both linear and nonlinear equivalent circuit models have been developed to characterize the RF and de behaviors of device. Modeled simulation results show correspondence with the experimental data. This monolithic downconverter is comprised of an RF LNA, a dual-gate MESFET mixer, an IF variable gain amplifies and a varactor tuned oscillator. The primary design specifications are (1) 50-dB conversion gain, (2) 4-dB noise figure, (3) more than 40-dB gain controllable range, and (4) 50-dBc third-order intermodulation distortion. The chip size is 1.4 x 1.5 x 0.18 mm(3). It is encapsulated in a standard low cost mm plastic package. Moreover, this downconverter IC is promising for miniaturization and cost-reduction of a DBS receiver The detailed measured characteristics will be presented in part-II of this paper.
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.
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.
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.
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
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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.
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
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LIU, EH
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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
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CHEN, JS
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WU, JW
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LIN, KC
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材料科學與工程學系
THE SELECTIVITY OF REACTIVE ION ETCH OF GA0.51IN0.49P/GAAS
(1994)
WU, JW
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CHAN, SH
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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
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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.