Browsing by Author "CHEN, TH"

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AN ULTRA-LOW COST AND MINIATURE 950-2050 MHZ GAAS MMIC DOWNCONVERTER .1. DESIGN APPROACH AND SIMULATION
(1995-05-01)
HSIEH, TH
;
WANG, H
;
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.
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.
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.