Field emission cold cathode element

Abstract

A field emission cold cathode element designed with the objects of enabling control of overcurrents that arise at times of discharge without adding a power source or complicating the operating circuits, realizing high-frequency operation and lower power consumption without giving rise to short-circuit damage due to discharge breakdown, and moreover, suppressing increases in element temperature; wherein an n-type region underlying emitters is divided between three n-type semiconductor regions: a first n-type semiconductor region, a second n-type semiconductor region and a third n-type semiconductor region. A third n-type semiconductor region below the emitters formed so as to be surrounded by a p-type semiconductor region, a second n-type semiconductor region below the third n-type semiconductor region formed so as to be surrounded by a p-type semiconductor region, and a first n-type semiconductor region formed below the second n-type semiconductor region; wherein the cross section of the second n-type semiconductor region is smaller than the cross section of the third n-type semiconductor region, thereby producing an n-type region made up of three n-type semiconductor regions that has a constricted shape.