| 摘要 |
<p>PURPOSE:To make it possible to reduce the thickness of a conductive thin film sufficiently and highly increase the number of emitted electrons by laying the conductive thin film on a P-type semiconductor layer through an intrinsic semiconductor layer to make the potential of the thin film higher than that of the P-type semiconductor layer, and emitting electrons accelerated in the intrinsic semiconductor layer from the thin film. CONSTITUTION:A P-type layer 5 of a determined shape is formed on a P<+>-type semiconductor substrate 4, on the top part of which a P<+>-type layer 1a is buried with exposing the surface thereof. The P-type layer 5 including this layer is enveloped in an I-type layer 2a for acceleration. A conductive thin film 3a is layed on the layer 5, which is covered with a conductive layer 6. A window is made in the layer 6 so as to correspond to a emitting face 1S on the surface of the layer 1a, exposing the thin film 3a therefrom. The emitting element is thus constituted, with the +side of an electric supply 7 being connected to the thin film 3a through the layer 6, and the -side being connected to the substrate 4. This constitution of the I-type layer 2a makes it possible to reduce the thickness of the thin film 3a without being affected by ion implantation, resulting in a great increase in number of electrons emitted through the window.</p> |
