Field emission device with suspended gate

摘要

An electron emitter plate (110) for an FED image display has an extraction (gate) electrode (22) spaced by a dielectric insulating spacer (125) from a cathode electrode including a conductive mesh (18). Arrays (12) of microtips (14) are located in mesh spacings (16), within apertures (26) formed in clusters (23) in extraction electrode (22). Microtips (14) are deposited through the apertures (26). The insulating spacer (125) is etched to undercut electrode (22) to connect apertures, forming a common cavity (141) for microtips (14) within each mesh spacing (16). Support beam structures (143) are deposited onto extraction electrode (22), either separately or simultaneously with formation of the microtips (14). The support beam structures (143) span the cavity (143) to support the extraction electrode (22) above the cathode electrode over cavity (143). The etch-out reduces the dielectric constant factor of gate- to-cathode capacitance in the finished structure. Strengthening the gate (22) with structures (143) enables gate support over the cavity (141).