Sang-Uhn Cha

39.2: The Full‐Color Video Images with Uniquely‐Gated Carbon Nano‐tube Field Emission Displays

Thick-film printing processes have been applied for preparing a carbon nanotube field emission display (c-FED), which has a strong cost advantage for large-size flat panel display. For practical display applications, two types of the gated cathode structure named the normal-gate cathode and the under-gate cathode have been developed and improved. The normal-gate and the under-gate cathode structures have the driving voltages of ±35 V and ±65 V, respectively. The 5″ c-FED panel with the normal-gate cathode and the 7″ c-FED panel with the under-gate cathode were successfully implemented and excellent full-color video images were obtained.

Defect Analysis and Cost-Effective Resilience Architecture for Future DRAM Devices

Technology scaling has continuously improved the density, performance, energy efficiency, and cost of DRAM-based main memory systems. Starting from sub-20nm processes, however, the industry began to pay considerably higher costs to screen and manage notably increasing defective cells. The traditional technique, which replaces the rows/columns containing faulty cells with spare rows/columns, has been able to cost-effectively repair the defective cells so far, but it will become unaffordable soon because an excessive number of spare rows/columns are required to manage the increasing number of defective cells. This necessitates a synergistic application of an alternative resilience technique such as In-DRAM ECC with the traditional one. Through extensive measurement and simulation, we first identify that aggressive miniaturization makes DRAM cells more sensitive to random telegraph noise or variable retention time, which is dominantly manifested as a surge in randomly scattered single-cell faults. Second, we advocate using In-DRAM ECC to overcome the DRAM scaling challenges and architect In-DRAM ECC to accomplish high area efficiency and minimal performance degradation. Moreover, we show that advancement in process technology reduces decoding/correction time to a small fraction of DRAM access time, and that the throughput penalty of a write operation due to an additional read for a parity update is mostly overcome by the multi-bank structure and long burst writes that span an entire In-DRAM ECC codeword. Lastly, we demonstrate that system reliability with modern rank-level ECC schemes such as single device data correction is further improved by hundred million times with the proposed In-DRAM ECC architecture.

P-39: Degradation Mechanism of Spindt-Type Molybdenum Field Emitter Arrays by Oxidation and Surface Chemical Modification

Oxidation and chemical modification of molybdenum micro tip surface have been investigated to understand the performance degradation mechanism of field emitter arrays(FEAs). Molybdenum FEAs could be easily oxidized due to their interaction with oxygen-containing species including O2, CO2 and H2O during cathode fabrication or thermal sealing processes of field emission displays(FEDs). During device operation, outgassing from phosphors due to electron-stimulated desorption and from other components inside a panel such as cathode, spacers, and sealant can lead to the chemical modification of the emitter surface. The oxidation and chemical modification of the emitter surface degrade the emission characteristics, resulting in the instability of an emission current, an increase of an electron extraction voltage for a given current, and lifetime reduction of the device. After the vacuum sealing and operation of the FED device, a micro tip is observed, and compared with an as-grown one by using scanning electron microscopy(SEM) and transmission electron microscopy(TEM). Chemical composition analyses of the degraded emitter surface by nano-probed Auger electron spectroscopy(AES) suggest that molybdenum micro tip is contaminated with S, In, C, and O after the device operation, where S and In seem to originate from the dissociation of phosphors by electron bombardment.

P‐45: Performance of in‐situ Laser Vacuum Sealing and Annealing on the Panel for the Application of Field Emission Displays

In-situ laser sealing and annealing treatments have been performed inside a high vacuum chamber for efficient completion process of field emission displays. A high power Nd:YAG continuous wave (λ = 1,064nm) laser was mainly used as an irradiation source was used as a source. In a packaging scheme, the most vital part of the panel was kept at temperature below 300°C to shorten the entire panel process. Experimental work exhibits efficiently local hitting of frit by the laser to stitch both cathode and anode plate during the short time. In addition, laser treatment on electrophoretically deposited phosphors has been carried out as one of efficient post-annealing methods in order to improve the brightness of the phosphor coated on indium-tin oxide-coated glasses. For the annealing process, two basic parameters, such as laser power and treatment time were examined inside the same vacuum chamber. The experimental results presented useful laser-annealing time and enhanced improvement of about 10% in the brightness after the laser irradiation on the phosphor. The improvement in the brightness was thought due to the surface cleaning effect on the phosphor surface.

P‐41: Improvement of Low‐Voltage Phosphors by Ar‐Gas Sputtering Treatments after Electron Bombardment: ZnS:Cu,Al and ZnGa2O4:Mn

Electrophoretically deposited low voltage phosphors of FED are irradiated by electron beam from the Spindt micro tip arrays. The conditions of phosphor surface are analyzed at various conditions. Ar gas treatment is used for stabilizing the surface of ZnS:Cu,Al and ZnGa2O4:Mn with improved conditions. It is found that the electron irradiation on the phosphor seriously causes carbon effect to the phosphor surface, resulting in dark color defects on the real 4 inch FED panel. However, the contaminated phosphor surface is effectively eliminated by the gas sputtering treatment on it, and proved experimentally.