Search

To develop plasma-resistant glass materials suitable for semiconductor etching processes, we introduced alkaline earth oxides (ROs) into a Li2O–Al2O3–SiO2 (LAS) glass. Analysis of glass properties with respect to the additives revealed that among the analyzed materials, the LAS material in which Li2O was partially replaced by MgO (MLAS) exhibited the most favorable characteristics, including a low dielectric constant (6.3) and thermal expansion coefficient (2.302 × 10−6/°C). The high performance of MLAS is attributed to the high ionic field strength of Mg2+ ions, which restricts the movement of Li+ ions under the influence of electric fields and thermal vibrations at elevated temperatures. When exposed to CF4/O2/Ar plasma, the etching speed of RO-doped glasses decreased compared with that of quartz and LAS glass, primarily owing to the generation of a high-sublimation-point fluoride layer on the surface. Herein, MLAS demonstrated the slowest etching speed, indicating exceptional plasma resistance. X-ray photoelectron spectroscopy analysis conducted immediately after plasma etching revealed that the oxidation-to-fluorination ratio of Li was the lowest for MLAS. This observation suggests that the presence of Mg2+ ions in the plasma discharge inhibits the migration of Li+ ions toward the surface, thereby contributing to the excellent plasma resistance of MLAS. [ABSTRACT FROM AUTHOR]

The microplasma modes generated in a plasma display with a coplanar gap and an auxiliary electrode were investigated using the discharge current peak time (discharge delay) and discharge current. Three types of modes were classified as follows: Mode 1) showed a decrease in both the discharge current and the discharge delay, Mode 2) showed a decrease in the discharge current and an increase in the discharge delay, and Mode 3) showed an increase in the discharge current and a decrease in the discharge delay. The infrared efficiency increased in Modes 1) and 2) with an increase in the auxiliary pulse voltage. However, in Mode 3), the IR efficiency started to decrease. According to the measurement results, Modes 1) and 2) are suitable for microplasma generated in a coplanar gap with an auxiliary electrode to obtain high efficacy. Index Terms--Auxiliary electrode, coplanar gap, discharge current peak time, discharge delay, infrared (IR) efficiency, IR peak time, microplasma, plasma display.

The discharge characteristics of a multielectrode dual coplanar in a mercury-free flat fluorescent lamp were investigated using brightness-efficiency measurement and the infrared (IR) spectrum and intensified charge coupled device (ICCD) characteristics. The level of brightness was above 14 900 cd/m2 under the conditions of neon-–50% xenon–8% He gas composition, 150 Torr pressure, and 20 kHz alternating current pulse. The ICCD results revealed a faster and wider discharge with a Ne–50% Xe–8% He gas composition. The effect of adding helium (He) to Ne–50% Xe revealed a faster peak emission, as confirmed by ICCD images. From the gated IR emission spectrum, the intensity ratio of I823 nm/I828 nm was ∼8% higher with Ne–50% Xe–8% He than with Ne–50% Xe under the same pressure and applied voltage conditions. [ABSTRACT FROM AUTHOR]

This study investigated the crystalline orientation and electromechanical characteristics of PZT films fabricated with various concentrations of sol-gel solution, and dopants such as Nb and Zn. Crack-free and 1-μm-thick films with a pure perovskite phase were obtained on Pt/Ti/SiO2/Si by modified sol-gel deposition method. The degree of (111) orientation was promoted by a higher concentration of a sol-gel solution. Excellent electromechanical characteristics were measured in PZN-PZT films. The highest remnant polarization and d33 piezoelectric coefficient were 25.1 μC/cm2 and 240 pC/N, respectively. The sol-gel driven PZN-PZT films could be attractive for application to piezoelectrically operated microelectronic devices. [ABSTRACT FROM AUTHOR]

The SiO2 generated by low-temperature oxidation of ultra-thin metallic silicon (thickness = 50 nm) film was evaluated for implementation in one-glass-solution capacitive touch-screen panels (OGS-TSPs) on sapphire-based substrates. Our results show that the silicon films oxidized at 823 K exhibited the highest visible transmittance about 91% at 550 nm, compared to ~72% transmittance of the as-deposited silicon films which were deposited at room temperature. Additionally, the annealed films exhibited a more uniform, dense, and smooth surface microstructure than that of the as-deposited Si films. X-ray photoelectron spectroscopy (XPS) results revealed that the low-temperature oxidation of Si films at 823 K yielded SiO2. Furthermore, when the insulating SiO2 film obtained by low-temperature oxidation was sandwiched between two indium tin oxide (ITO) layers (ITO/SiO2/ITO) on a sapphire substrate, the SiO2 film resulted in the dielectric strength of approximately 3 MV/cm. In addition, the highest optical transmittance obtained by the ITO/SiO2/ITO films is about 88.3%. The change in capacitance of the ITO/SiO2/ITO structure was approximately 3.2 pF, which indicates the possibility of implementation in capacitive touch-screen panel devices. [ABSTRACT FROM AUTHOR]

We report a new method for measuring vacuum pressures using Van der Waals (VDW) interactions between reduced graphene oxide (RGO) sheets. For this purpose, we utilized a reaction-based self-assembly process to fabricate various intercalated RGO (i-RGO) films, and monitored their electrical behavior with changing pressure and temperature. Pumping to remove gas from a vacuum chamber produced a decrease in the sheet resistance of i-RGO. With further pumping, distinctly different sheet resistance behaivors were observed depending on the measurement temperature. With increasing vacuum pressure, the resistance increased at 100 °C, whereas it decreased at 30 °C. Two types of VDW interactions are proposed to explain these features: a local VDW interaction between RGO sheets that resulted in V-shaped curves of sheet resistance with pressure changes and broad VDW interactions that occur between RGO sheets when the elastic force required to bend carbon clusters on an RGO sheet exceeds their vibrational energy at low temperatures. On the basis of the results, we propose that the resistance behavior of i-RGO as a function of vacuum pressure can be interpreted as the sum of the two different VDW interactions. [ABSTRACT FROM AUTHOR]

Lead-free piezoelectric 0.06(LiNbO3)–0.94(Na0.5K0.5)NbO3 (LNKN) ceramics in disc form were fabricated and characterized to acquire good electromechanical properties. A molding method including cold isostatic pressing (CIP) was used to form a dense and regular microstructure and suppress the cracking problems of LNKN ceramics during the following high-temperature sintering. The LNKN ceramic sintered at 1040 °C showed a high piezoelectric constant d33 of 170 pC/N owing to its high density. Furthermore, perovskite LNKN films with the same composition as the ceramics were fabricated using 2-methoxyethanol-based sol–gel solution. The sol–gel surface coating on the LNKN ceramics was found to be very effective for increasing the piezoelectric constant because of the interface stabilization effect leading to a uniform electric field in piezoelectric elements. As a result, we obtained the highest piezoelectric constant d33 of 183 pC/N. The lead-free LNKN ceramics are promising for applications in eco-friendly ferroelectric and piezoelectric devices. [ABSTRACT FROM AUTHOR]

In this study, we report that the metal Cu deposited on a glass substrate is formed into a stable p-type Cu2O film with excellent properties through rapid thermal oxidation (RTO). The pre-deposited Cu film layer went through thermal oxidation in the temperature range of 200–500 °C in O2 and air ambient, and the electrical and optical properties were intensively investigated. The optimized p-type Cu2O film heat-treated at a temperature of 200 °C in an air ambient has a carrier concentration of 1.25×1017 cm-3, mobility of 0.51 cm2 V-1 s-1, and resistivity of 9.86 Ω cm; its optical band gap reaches about 2.4 eV. Using the p-type Cu2O film with i- and n-type amorphous silicon layers, heterojunction thin-film solar cells were fabricated on glass substrates. These transparent solar cells employed Ga-doped ZnO films as top and bottom electrodes. Solar cells with Cu2O film oxidized at 200 °C in an air ambient have an open circuit voltage of 0.36 V, short-circuit current of 15.2 mA/cm2, and photoelectric conversion efficiency of 1.98%. [ABSTRACT FROM AUTHOR]

Pure SnO2 nanoparticles with a single tetragonal phase were fabricated and characterized for use as ink solution. It was possible to obtain the SnO2 nanoparticles through the calcination process of SnC204 powders prepared by a hydrothermal reaction of an aqueous solution containing SnCl2 x 2H2O and H2C2O4. The SnO2 powder, synthesized at 600 degrees C, showed a single tetragonal phase, while the powders synthesized at 550 degrees C or lower were composed of a mixture of tetragonal and orthorhombic phases. The particle size of the SnO2 powder with single tetragonal phase was as small as 100 nm and its surface specific area was 12.31 m2/g. It was possible to fabricate the SnO2-nanoparticle-included ink solution for nanoparticle printing by adding a small amount of the previously prepared SnO2 powder to an aqueous solution of glycerol. The region of SnO2 nanoparticles formed by dropping the ink solution was able to successfully fill the gaps between Pt electrodes patterned on SiO2/Si substrates; the range of the gap between the electrodes was from 10 to 100 μm.

We have proposed, prepared, and characterized Pt-inserted Ga-doped ZnO (GZO) transparent electrodes of GZO/Pt/GZO (GPG) multilayers on glass and flexible plastic substrates. Pt-inserted GZO electrodes showed remarkably decreased resistivity, even though the thickness of the Pt layer was only a few nm. However, the optical transmittance of the GPG electrodes was degraded with increasing thickness of the Pt layer. The structural, optical, and electrical properties of GZO film and GPG multilayered transparent electrodes on glass substrates were largely affected by post- annealing conditions such as the ambient and temperature. Post-annealing in a N2 ambient was the most effective treatment for achieving high optical transmittance and low electrical resistivity of the GZO films and GPG structure. Good optical transmittance of 78% and electrical resistivity of 3.5 x 10(-3) Ω·cm of the GZO electrode were obtained for the 4-nm-thick Pt insertion layer and post-annealing at 400 °C. In addition, touch sensor devices were fabricated by using GPG structures and flexible plastic substrates. The touch sensor devices exhibited a capacitance ratio of 1.4 between the two states before and after fingertip touching.

This study investigated the morphological and electromechanical characteristics of 0.2PZN-0.8PZT films fabricated using a PbTiO3 layer. Crack-free 1-microm-thick films with a pure perovskite phase were obtained on Pt/Ti/SiO2/Si substrates using a modified sol-gel deposition method. A highly dense and smooth morphology and a high piezoelectric coefficient (d33) of 230 pC/N were observed in a 0.2PZN-0.8PZT film with a PbTiO3 insertion layer after annealing at 750 degrees C. The as-produced sol-gel-driven 0.2PZN-0.8PZT thin films are attractive for application to piezoelectrically operated microelectronic actuators, sensors, or energy harvesters due to their low facility cost, smooth surface, and excellent electromechanical characteristics.