Electron tube having a semiconductor cathode with lower and higher bandgap layers
AssigneeU.S. Philips Corporation
InventorsRon Kroon, Tom Van Zutphen, Erwin A. Hijzen
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Abstract
A semiconductor cathode (11) in a semiconductor structure, in which the sturdiness of the cathode is increased by covering the emitting surface (4) with a layer of a semiconductor material (7) having a larger bandgap than the semiconductor material of the semiconductor cathode. Various measures for increasing the electron-mission efficiency are indicated.
Claims8
A semiconductor device for generating electrons comprising a semiconductor body of a first semiconductor material having at least one structure for emitting electrons, which structure is adjacent to a main surface of the semiconductor body and in which electrons can be generated by applying suitable electric voltages, which electrons emanate from the semiconductor body at the location of an emitting surface region, characterized in that the structure for emitting electrons is covered with at least one layer of second semiconductor material having a larger bandgap than the first semiconductor material.
Dependencies are inferred from the claim text.