Browsing by Author "HSIEH, IJ"

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A NEW FABRICATION TECHNOLOGY FOR FIELD-EMISSION TRIODES WITH EMITTER-GATE SEPARATION OF 0.18-MU-M
(1995-01-01)
WANG, CC
;
LEE, WF
;
KU, TK
;
CHEN, MS
;
FENG, MS
A new fabrication technology has been used for field-emission triodes with the emitter-gate separation as small as 0.18 mum to reduce the turn-on and anode voltages. The technology is based on the thermal oxidation of silicon and low-pressure chemical vapor deposition (LPCVD) of polycrystalline silicon, making the fabrication of a sub-half-micronmeter gate opening easy and reproducible. The entire process requires use of only one photolithography mask, and does not require advanced high-resolution photolithographic techniques. In this device, the oxidation process serves the three purposes of sharpening the emitters, defining the emitter-gate separation, and achieving a high-quality insulator. The finished devices have the emitter situated exactly at the center of the gate opening due to a self-alignment process. Furthermore, the LPCVD polysilicon film can form gate electrodes with a smooth edge and a small gate opening due to excellent step coverage.
CATHODOLUMINESCENT CHARACTERISTICS OF ZNGA2O4 PHOSPHOR GROWN BY RADIO-FREQUENCY MAGNETRON SPUTTERING
(1994-09-15)
HSIEH, IJ
;
CHU, KT
;
YU, CF
;
FENG, MS
;
材料科學與工程學系
Low voltage cathodoluminescent characteristics of ZnGa2O4 phosphor grown by rf magnetron sputtering have been investigated from 300 to 700 nm. The effects of substrate heating and annealing treatment on the luminescent characteristics are also studied. A blue cathodoluminescent emission peaked at 470 nm is observed. Better luminescent properties are achieved on the films which have crystal structure with a standard powder x-ray diffraction pattern of ZnGa2O4. The effect of the strength of the ligand field on the resultant energy levels for the ZnGa2O4 phosphor is investigated. Low-voltage phosphor films with excellent cathodoluminescent characteristics have been successfully developed in this research.
GROWTH OF ZNGA2O4 PHOSPHOR BY RADIO-FREQUENCY MAGNETRON SPUTTERING
(1994-06-01)
HSIEH, IJ
;
FENG, MS
;
KUO, KT
;
LIN, P
;
材料科學與工程學系
ZnGa2O4 films have been prepared by radio frequency (RF) magnetron sputtering at various total pressure, RF power, and substrate temperatures. Microstructure and crystallographic orientation were characterized by x-ray diffraction Surface morphologies were observed by scanning electron microscope. In addition, cathodoluminescence (CL) measurement was employed to observe the emission spectra of ZnGa2O4 films. The influences of various deposition parameters on the properties of grown films were studied. The optimum substrate deposition temperature for luminous characteristics was about 500-degrees-C in this investigation. A blue cathodoluminescent emission peaked at 470 nm was observed. Good luminescent properties were observed in the films which exhibit the standard ZnGa2O4 x-ray diffraction pattern.
SIMULATION OF THE ELECTRICAL CHARACTERISTICS OF FIELD-EMISSION TRIODES WITH VARIOUS GATE STRUCTURES
(1995-10-01)
KU, TK
;
CHEN, MS
;
WANG, CC
;
FENG, MS
;
HSIEH, IJ
A new two-dimensional numerical simulation which can accurately reproduce the empirical electrical characteristics of vertical field-emission triodes (FET's) with various gate geometries has been developed. The electrical characteristics of volcano-shaped-gate FET's were simulated for the first time and compared with those of planar-gate ones. Volcano-shaped-gate FET's exhibit significant advantages over planar-gate ones due to their superior current-voltage (I-V) properties and larger tolerance of fabrication error. A reasonable definition of emission area was obtained by applying the non-uniform current density model. For sub-micron gate aperture, the gate current is obvious only if the device structure is deeply tip-recessed. On the basis of the evaluation of the device structures including the tip cone angle, the related tip-to-gate height, the emitter shape, and the shrinkage of gate aperture, a high-aspect-ratio conical emitter with a small tip radius will be the optimum structure of FET's for low-voltage operation.