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.