Byeong Kwon Ju

A noble suspended type thin film resonator (STFR) using the SOI technology

Abstract The fabrication and characteristics of suspended type thin film resonators (STFRs) using surface micromachining of the SOI technology, have been studied. The size of the active part of STFRs is 160 μm ×160 xa0μm. For the piezoelectric AlN thin film, the following etch rate was observed 200xa0nmxa0min −1 in 0.6xa0wt.% TMAH. The thickness of the piezoelectric AlN film for the STFR is 2xa0μm. Cr thin film is used as the top and bottom electrode. This device is free-standing and has a resonant frequency of 1.65xa0GHz for the 2xa0μm AlN thin film, a K eff 2 of 2.4%, Q s of 91.7, Q p of 87.7.

Fabrication of suspended thin film resonator for application of RF bandpass filter

Abstract Characteristics of AlN thin film and thin film resonator for RF bandpass filter have been studied. AlN thin films were deposited by RF magnetron sputter system. Deposition parameters such as N2 contents, Ar and N2 partial pressures, and the distance between metal target and substrate were found to affect the piezoelectric response. To fabricate the suspended thin film resonator (STFR) using the piezoelectric AlN thin film, the etching of AlN and the surface micromachining process were conducted. The thickness of AlN film and membrane for the STFR are 2 and 15 μm, respectively. This membrane was fabricated by SOI technology. The device with the dimension of 160xa0×xa0160 μm2 has a resonant frequency of 1.653 GHz, a Keff2 of 2.4%, a bandwidth of 17 MHz, and a quality factor of 91.7. The device with the dimension of 200xa0×xa0200 μm2 has a resonant frequency of 1.641 GHz, a Keff2 of 1.2%, and a bandwidth of 9 MHz, and a quality factor of 50.2.

The influence of ambient gases during the frit‐sealing cycle on the emission characteristics of Mo‐FEAs

— A 3.5-in. full-color field-emission display (FED) has been developed. The Spindt-tip array with a pixelated anode produces uniform and clean image. Changes in electron emission characteristics before and after the frit-sealing cycle were measured on the same field-emitter arrays (FEAs). Properties of thin Mo films after frit sealing in various gaseous ambients were estimated by AFM, AES, SIMS, and XPS. The possibility of applying Ar as an ambient gas during the frit-sealing cycle for vacuum packaging of field emission displays (FEDs) was reported. A set of uniquely printed spacers with high aspect ratios was fabricated on ITO-coated glass for high-vacuum packaging. The low-voltage phosphor was tested at an anode voltage of 300 V. Finally, full-color images of 64 gray scales will be demonstrated.

Glass-to-glass electrostatic bonding for FED tubeless packaging application

Abstract Two ITO-coated glass wafers (Corning #7740, #0080) are successfully bonded by the typical Si-Pyrex electrostatic bonding mechanism. Both Si-#7740 and Ti-(Li-doped SiO 2 ) interlayer systems can be employed for the electrostatic bonding of #7059-#7059 and #0080-#0080 glass wafer pairs. This glass-to-glass electrostatic bonding process can be applied to the clean and tubeless packaging of field emission display panels.

The Influence of Gate Insulator Etching on the Characteristics of Mo Tip Field Emitter Arrays

Electron emission characteristics of field emitter arrays (FEAs) as etched shape of gate-insulating opening were investigated by the measurement of anode and/or gate leakage current and voltage. In this study, we introduced a hybrid etching process, which etches the gate insulator wet and dry process sequentially. We also compared electron emission characteristics of FEAs as a function of etching process to form the gate-insulating opening. The current density of field emitter arrays (FEAs) with new type of gate-insulating opening is lower than that of FEAs with vertically etched shape of gate-insulating opening. The electric field of FEAs made by hybrid process is higher than that of FEAs by using wet etching process to form the gate-insulating opening. Thus, introduced hybrid-etching process can optimize the gate-insulating opening of FEAs.

Fabrication and estimation of characteristics for Nb-silicide FEAs

Electron emission currents and stability in the silicon-tip field emission arrays (FEAs) have been improved by silicide formation on silicon using Nb. The formation of Nb-silicide was confirmed by X-Ray diffraction data. The turn-on voltage of silicon-tip FEAs was decreased from 64 to 47 V and the emission current fluctuation was decreased from 5% to 2%.

Effect of N-Doped Hydrogen-Free DLC Coating on Mo-Tip FEAs

Nitrogen gas phase doped diamond-like carbon (DLC) coating on molybdenum-tip field emitter arrays (FEAs) has been used to improve electron emission characteristics. The conventional plasma enhanced chemical vapor deposition (PECVD) method using a layer-by-layer technique was applied to deposit N-doped hydrogen-free DLC films. Electron emission characteristics were measured and possibility of applying this type of emitters to high frequency field emission displays (FEDs) was reported. The turn-on voltage of Mo-tip FEAs was decreased from 75V to 55V by DLC coating and emission current was more stable than that of conventional Mo-tip FEAs. The transconductance of Mo-tip FEAs was increased by N-doped hydrogen-free DLC coating with lowering effective work function of emitters.

Fabrication and field emission properties of poly-diamond films

Abstract By using a substrate transferring technique, poly-diamond thick films having a smooth or rough surface could be fabricated as field emitter materials. The diamond film with a smooth surface, which was transferred from the interface between the (100) Si substrate and poly-diamond deposited by plasma-enhanced CVD, showed better field emission properties in terms of emission current density with improved vacuum level dependence as compared with original poly-diamond film from a rough surface.