Method for manufacturing field emission device

A method for fabricating a field emission device (FED), comprising:

• forming a cathode, a gate insulation layer with wells, and a gate electrode with gates on a substrate in sequence, and forming micro-tips on the cathode exposed by the wells;
• forming a focus gate insulation layer on the gate electrode to have a predetermined thickness with a carbonaceous polymer layer, such that the wells having the micro-tips are filled with the carbonaceous polymer layer;
• forming a focus gate electrode on the focus gate electrode;
• forming a predetermined photoresist pattern on the focus gate electrode;
• etching the focus gate electrode into a focus gate electrode pattern using the photoresist pattern as an etch mask;
• etching the focus gate insulation layer exposed through the focus gate electrode pattern by plasma etching using O2, or a gas mixture containing O2 for the focus gate insulation layer and a gas for the micro-tips as a reaction gas, thereby resulting in wells in the focus gate insulation layer;
• etching the carbonaceous polymer layer within the wells of the gate insulation layer by plasma etching using O2, or a gas mixture containing O2 for the focus gate insulation layer and a gas for the micro-tips as a reaction gas, such that the carbonaceous polymer layer partially remains on the surface of the micro-tips;
• and
• etching the surface of the micro-tips by plasma etching using the carbonaceous polymer layer remaining on the micro-tips as an etch mask, and etching the carbonaceous polymer layer itself, using the reaction gas, thereby resulting in micro-tips with nano-sized surface features.