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We measured the surface charge distribution in a coplanar type alternating current plasma display panel cell by the longitudinal electro-optic amplitude modulation method with BSO (Bi12SiO20) single crystal. The effects of the initialization condition were investigated to take care of the errors coming from the charge relaxation phenomena of the BSO crystal. Using BSO single crystal as the dielectric layer, the two-dimensional spatiotemporal surface charge distribution was successfully measured in a discharge cell with a discharge gas of neon and xenon 4% at the pressure of 100torr driven by square-type sustaining pulses. The temporal behavior of the surface charge is compared with the simulated result and the measurement of the infrared light emission from the discharge. The positive and negative surface charges show somewhat different spatiotemporal characteristics.

To improve the discharge characteristics of Zn 2 SiO 4 :Mn 2+ phosphor layers in ac plasma display panels, the charging tendency of phosphor was modified by coating the phosphor surface and manipulating the phosphor paste with metal oxide, and their effects on the driving voltages and addressing time were investigated in terms of the driving conditions of plasma display panel (PDP) cell. It was found that the magnesium oxide, which has a positive charging tendency, was very effective and could dramatically improve the surface characteristics of the phosphor layer for stable discharge of the PDP cell. Consequently, the delay time of addressing current was reduced more than 30% and the minimum values of sustaining voltage as well as addressing voltage could be decreased by 12 V on average, while the luminous efficiency was kept constant and even improved in the case of MgO-coated phosphor.

We are proposing a new reset method for AC PDP, which is composed of multiple short pulses with fast ramp bias voltage. We have succeeded in achieving low background luminance as well as stable and higher address margin. When compared with the conventional ramp reset method, the darkroom contrast ratio can be increased by 52% and the reset time can be shortened by 215μs for each subfield.

We have accomplished the various experiments of the test panel with hexagonal shape subpixels for optimizing the luminance and efficiency characteristics of the delta color array PDP. The optimal pixel and electrode designs are obtained for the highdefinition PDP with fine pixel pitch less than 0.7 mm in 42-inch. The hexagonal array structure shows more improved luminous efficiency results than that of the normal delta array structure with rectangular subpixels.

We measured the spatiotemporal wall charge distributions on sustain and address electrodes in an ac PDP cell using the longitudinal electro-optic amplitude modulation method. The measured wall charge distributions are used together with the discharge images obtained using high speed, image intensified CCD camera to have a better understanding on the sustain as well as the address discharge occurring in a three electrodes, coplanar sustain discharge type ac PDP cell.

Sealing of two glass plates composing of PDP panel was done in a vacuum chamber by using an auxiliary heating line(AHL). In order to improve the uniformity of sealing temperature and reduce the panel temperature during sealing, the AHL was introduced by a screen printing method inside a frit glass and used as a part of heating source for the frit melting. Outgassing and bubbling can be also severe problems during the heating process of the frit glass inside a vacuum chamber. Our specially prepared frit glass was successfully applied for the vacuum in-line sealing approach without bubbles. By using the AHL technology and the specially prepared frit glass, we have successfully sealed a PDP test panel without bubbles and any leak through the frit glass.

We investigated the secondary electron emission characteristics of MgO layer used as the protecting material in a.c. plasma display panel(a.c.-PDPs) using a pulsed ion beam technique, where the surface charging can be effectively suppressed during the measurement. The measurement of the secondary electron emission coefficients γi for He+, Ne+, Ar+, Kr+ and Xe+ ions with kinetic energies ranging from 50 eV to 225 eV showed an energy dependency increasing gradually as a function of kinetic energy. In addition, it was clearly demonstrated that the pulsed ion beam method can successfully measure the coefficient of secondary electron emission from insulator surfaces.

The new driving method is proposed based on the luminance compensation against subfield variation for balancing the white color in an AC PDP. The luminance ratio among the red, green, and blue light can be controlled independently by applying the different auxiliary address pulses to the red, green, and blue cells during a sustain-period. As a result, the minimum perceptible white color difference (Δuv < 0.002) with respect to the reference white color at SF5 is obtained irrespective of the variation in the subfield from SF1 to SF8.

Properties of electrical breakdown voltage in a mixed gas are investigated based on Townsend criterion. The breakdown temperature Tb and voltage Vb are obtained in terms of the gas mixture ratio χ . As an example, we investigate electrical breakdown properties in neon gas mixed with xenon. It is shown that the breakdown voltage decreases, reaches the minimum value at χ = 0.02 and then increases again, as the mixture ratio χ increases from zero to unity. A preliminary experiment of AC-plasma display panel (PDP) is carried out for neon gas mixed with a few percent of xenon to verify some of the theoretical models. The experimental data agree qualitatively well with theoretical predictions. One of the most important issue of the industrial applications of plasma is reduction of the electrical breakdown-voltage in high pressure gas. As an example, we consider the electrical discharge system in high-pressure inert-gas in connection with its applications to the plasma dis- play panel (PDP). 1-3) Reduction of the breakdown voltage in a low pressure gas by the Penning effects was reported in previous literature, 4) where one hundredth of one percent of argon gas is mixed with neon. However, the plasma dis- play panel is operated at high-pressure gas and the breakdown voltage reduction in a mixed gas is mostly accomplished by collision-frequency decrease. The UV light emitted from xenon discharge plasma is converted into fluorescence, which provides an image on TV screen. The discharge plasma is generated by the electrical breakdown. Reduction of the dis- charge voltage is therefore the key element in enhancing the electrical efficiency of PDP. The electrical efficiency en- hancement in turn prolongs the panel lifetime. Size of xenon atoms is relatively large so that electrons in the plasma are highly collisional. Therefore, electron mean free-path is small in xenon gas, requiring high breakdown voltage. Plasma gen- eration in a mixture of xenon and light-atom gases may not need high breakdown voltage. We therefore investigate elec- trical discharge properties in a mixed gas. The ionization energy of heavy atoms is usually low, al- though their atomic size is large. Plasmas are generated from ionization of neutrals by the impact ionization of electrons, which have their kinetic energy higher than ionization en- ergy. Electrons with energy higher than ionization energy collide with neutrals, ionizing them. Therefore, it is easy to ionize neutrals with less ionization energy. Meanwhile, elec- tron energy-gain in large-size neutrals is difficult due to small mean free-path. The electrons can easily get their kinetic energy in a light-atom gas mixed with heavy atoms. Once having enough kinetic energy, they collide with heavy atoms of low ionization energy, producing additional electrons and ions.

A new AC PDP pixel structure with Segmented electrode in Delta color arrayed Rectangular subpixel (SDR) shows high luminance and luminous efficiency simultaneously compared with those of the conventional type AC PDP. The luminous characteristics of a new SDR structure were analyzed with 3-dimensional numerical simulation and ray optics calculation. Also, the test panels of SDR structure were fabricated and their addressing charcateristics were examined.

Three-dimensional fluid code was used to investigate the effect of barrier ribs on the addressing and the sustaining discharges. The barrier rib height and the cell pitch are the main parameters used in this study. The lower barrier rib height allows the faster addressing but requires the higher sustain voltage, while the wider cell pitch allows the lower address and sustain voltages. We used the voltage transfer curve to analyze the sustain period.

An alternate application of dichroic mirror for the improvement of luminance and luminous efficacy in an ac plasma display panel (PDP) is suggested. Since only part of the vacuum ultraviolet (VUV) generated in the PDP cell is used to excite the phosphor, we propose deploying a dichroic mirror that increases luminance and efficiency by reflecting part of the VUV toward the phosphor. The optical constants of the dielectric layers of the dichroic mirror and a protecting layer of a PDP were determined from the measurements of reflectance and transmittance of the corresponding films and they were used to design the dichroic mirror including the protecting layer. The 147 nm xenon resonance line is usually used to activate the phosphor in the PDP cell. Thus, we designed the dichroic mirror to have a high reflectance for the VUV centered around 147 nm and a high transmittance for the visible light. We investigated the usefulness of the dichroic mirror by comparing the luminance and luminous efficacy of test panels with and without the dichroic mirror and found it could increase the luminance by 20%–31% and the luminous efficacy by 25%–34%.

The decrease in operation voltages, such as firing and sustain voltages, and their instability has been observed frequently and is believed to be typical of the initial operation of an alternating current plasma display panel (ac PDP). To explain this decrease, we investigated the surface morphology, preferred crystal orientation, chemical species, and outgassing impurities of protecting MgO thin films, along with ac PDP manufacturing steps, using scanning electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, and a quadrupole mass spectrometer (QMS). Even though no significant changes were observed in the surface morphology, a drastic reduction in carbon impurity, as well as the initial high carbon concentration in the film, was observed. Furthermore, localization of the contaminants in the vicinity of the surface was observed during the heat treatment. With regard to the carbon contaminant, the QMS experiments showed consistent results. In the experiment measuring the secondary electr...

A phosphor screen prepared by the electrophoretic deposition technique, as one of the promising screen processes, was analyzed for plasma display panel (PDP) application with high resolution. The electrophoretic process was systematically described in terms of the process variables based on quantitative analysis, and the optical characteristics of the screen were investigated under vacuum ultraviolet (VUV) excitation. Photoluminescent (PL) intensities of phosphor screens were dependent upon the sustaining voltage, the screen weight, and the contents of the binder with which the phosphors were charged for electrophoretic attraction. The relative PL intensity exhibited a maximum value at the screen weight of 4 mg/cm 2 under VUV excitation. Also, the analytical equation for expressing the optical performance of phosphor screen has been derived as a function of material properties as well as screen geometry. It could be used to optimize the design parameters of the phosphor screen for PDP application. The theoretical approach from the phosphor screen model is compared with the experimental data.

— The spatio-temporal variations of 147-nm, 173-nm, and IR emission images were obtained from He-Xe and Ne-Xe surface-discharge-type ACPDP cells. Differences between the 147-nm, 173-nm, and IR emission characteristics between He-Xe and Ne-Xe gas mixtures were observed and explained by the difference of Xe mobility and dimer reaction coefficients in two cases.

The spatio-temporal variations of 147nm, 173nm, and IR emission images were obtained from He-Xe and Ne-X surface discharge type AC PDP cell. Differences in the 147nm, 173nm, and IR emission characteristics between He-Xe and Ne-Xe gas mixture were observed and explained by the difference of Xe mobility and dimer reaction coefficients in two cases.

Characteristics of selective SiO2 etching over Si3N4 in a magnetized inductively coupled high density C4F8 plasma have been investigated as a function of process parameters. The SiO2 etch rate increases with both external dc magnetic field (0–15 G) and rf discharge power at a pressure of 1.2 mTorr. For Si3N4, the etch rate also increases with rf power at unmagnetized and weakly magnetized (6 G) plasma conditions, but it decreases with discharge power when the magnetic field is higher than 12 G. At the substrate bias voltage of −100 V, the lowest etch rate of Si3N4 is obtained at two different process conditions namely low power, unmagnetized and high power, magnetized discharges. As the pressure increases, selectivity is degraded severely due to the rapid increase in the Si3N4etch rate. Resulting selectivities varied from approximately 1:1 to 40:1 without altering the feed gas chemistry. Measurement of fluorine density and CF, CF2 flux incident on the substrate reveal that the improvement of SiO2/Si3N4 etch selectivity is correlated to the rate of change of both CF and CF2 radicals being greater than that of fluorine. It is also shown that the high ion current at sufficiently low fluorine density is important for high selectivity. These results imply that the high density low pressure plasma source is indeed important for the selective etching of SiO2/Si3N4.

— A new cell structure for a monochrome DC-PDP with a wall cathode and a wall auxiliary anode is suggested. The wall cathode has a sufficient discharge-electrode area to allow maximization of the discharge volume. The wall auxiliary anode surrounds the discharge region, which can effectively control the charged particles in the discharge region. We investigated the characteristics of the new cell structure with a two-dimensional computer simulation and with experiments on a test panel and compared them with those of an earlier cell structure which has a co-planar anode and an auxiliary anode. Special emphasis was given to the effect of the wall auxiliary anode on the discharge characteristics. The new cell structure shows high luminance and improved discharge characteristics such as a short discharge build-up time and decreased minimum sustain voltage. The wall auxiliary anode plays the same role as in the coplanar-anode-type structure, but it demonstrates a better performance.

We measured the time variation of 147nm VUV Xe*(3P1) resonance emission as well as the continuum from the He-Xe discharge in a single surface discharge type AC PDP cell using an image intensified CCD camera. A detailed measurement of the resonance radiation exhibits a strong pressure broadening, fast rising to its peak and decay with multiple time constant. The decay time constants, relative intensities of resonance and dimer radiation change with the total gas pressure as well as the Xe content which implies that the collisional excitation, deexcitation and interlevel transition play important role in determining the VUV emission characteristics. We solved the He-Xe discharge reaction equations together with the 2-dimensional multi-fluid equations for electron and ions to explain the experimental results and elucidate the dominant kinetic pathways which lead to the VUV emission in the AC PDP cells.

Low‐temperature, defect‐free, in situ cleaning of silicon prior to homoepitaxy is successfully developed by an electron cyclotron resonance hydrogen plasma treatment in an ultrahigh vacuum chamber. The plasma potential distribution was measured by a Langmuir probe method to understand the effect of the substrate dc bias during hydrogen plasma cleaning. It changes from downhill to uphill distribution as the dc bias changes from a negative to a positive value, which leads to a decrease in the ion number density arriving at the substrate and results in the complete suppression of the defect formation in the Si substrate. In situ hydrogen plasma cleaned Si wafer always resulted in higher quality epilayers than ones cleaned only by so‐called hydrogen passivation after the HF dip. We found that there is a critical dose of the hydrogen ions during in situ plasma cleaning beyond which crystalline defects are observed in the Si substrate, subsequently leading to the poor crystallinity of the epilayers. The dose of the hydrogen ions during plasma cleaning can be effectively controlled by the substrate dc bias, the microwave power, the magnet current, and the cleaning time.