To provide a uniform and reproductive vacuum micro element with a gate conductive layer electrically insulated and arranged around a quantum size of thin terminal in such a manner that the short small diameter of the opening of an emitter is equal to or less than a shortest distance between emitter and gate metals.
A Si substrate 1 with n-type impurities doped at a high concentration is thermally oxidized to form a thermally oxidized film 2 of thickness 1.5μm, e.g. on the surface. Then, a 0.2μm thick MO as a gate conductive layer 3 is spattered all over and a 1.0μm thick SiN film 4 is laminated thereon with CVD. An array-patterned photoresist mask with an 2μm diameter of circular opening is formed and laminated films are etched in sequence by using PIE, antimony fluoride etching to expose the Si surface. This is anode-formed in hydrofluoric acid to make the surface porous. Only the shape of the end of an emitter is sharpened so that an obtained element has no leak current to a gate at 1μA per unit opening when 200V voltage is applied to an anode.
ONO TOMIO
CHO TOSHI
