Fabrication of micro-hole array for field emission cold cathode gates

A novel fabrication technique for high density gate hole arrays used in field emission cold cathodes is present here. This technique has been implemented by combining the micro electromechanical system (MEMS) processes with the microsphere lithography. Microsphere photolithography (MSP) generates a large area of highly uniform periodic sub-micrometer spot arrays by utilizing the monolayer of polystyrene (PS) latex microspheres as mask on top of silicon or silica. A large area of highly uniform sub-micrometer grid hole arrays (300-600 nm) with the array period of 0.75 m can be fabricated by the combination of lift-off and MSP. Microhole array density reaches to 108 holes/cm2. This is a promising method to fabricate a large area of highly uniform periodic and high-density gate hole arrays for field emission cold cathodes. The period is restricted by the microsphere diameter. The gate aperture can be tuned by shrinking the PS sphere using O2 reaction ion etching (RIE).