ELECTRON FLOW EMISSION SEMICONDUCTOR DEVICE

摘要

An electron source having good electron emission efficiency comprises a silicon or other semiconductor body (10) having an n-type first region (3) which is separated from an n-type or p-type second region (2) by a barrier. The barrier may be a p-n junction between p-type region (2) and the n-type region (3), or it may be a p-type region (1) forming p-n junctions with the n-type regions (2 and 3). By means of electrode connections (13 and 12) to the first and second regions (3 and 2) a potential difference (V) is applied across the barrier so as to bias the first region (3) positive with respect to the second region (2) and thereby to establish a supply of hot electrons (24) injected from the second region (2) across the barrier into the first region (3). These hot electrons (24) are emitted into free space (20) from a surface area (4) of the body (10) which may have a caesium coating (14) to reduce the electron work function. A surface region (5) which may be depleted even at zero bias adjoins the surface area (4) and comprises a p-type doping concentration which serves to form in the body (10) a potential peak which is spaced from the surface area (4) from which the hot electrons (24) are emitted to provide an adjacent drift field (15) which accelerates electrons (24) towards this surface area (4) so assisting the electron emission. The electron sources may be used in cathode-ray tubes, display devices and even electron lithography equipment.