ELECTRIC FIELD RADIATION ELECTRON SOURCE AND METHOD FOR FABRICATING IT

摘要

PROBLEM TO BE SOLVED: To provide a method for fabricating an electric field radiation electron source with high insulating internal pressure that the aging change of the electron emission efficiency is less. SOLUTION: A strong electric field drift layer 6 made of an oxidized porous polycrystalline silicon layer is deposited on the main surface of a conductive n-type silicon substrate 1, having a surface electrode 7 formed thereon. An ohmic electrode 2 is formed in the inside of the n-type silicon substrate 1. The drift layer 6 has an oxide layer of a dense SiO2 structure or a structure near to it obtained by heat-treating the porous polycrystalline silicon layer 4 formed by oxidizing the polycrystalline silicon layer 3 with the anode. Thus, the amount of hydrogen entering the drift layer 6 becomes less to prevent degradation of the electron emission efficiency caused by the aging change of the hydrogen distribution as well as enhancing the withstand voltage because of the dense oxide layer.