| 摘要 |
PURPOSE:To eliminate an irregularity and an instability of a breakdown strength when an electric field is controlled and to obtain a definite breakdown strength by installing at least one equalizing conductor which is extended along a prescribed geometrical line inside a plane of a high-resistivity thin film which is conductive to a first electrode and a second electrode which are situated so as to be separated. CONSTITUTION:When a source electrode 4 and a drain electrode 7, i.e., a drain ring 6, are set to a reverse-biased state, a potential gradient is distributed inside a plane of a high-resistivity thin film 9. Out of equipotential lines of this potential distribution, those situated between the source electrode 4, conductive rings and the drain ring 6 display an irregular curve which is decided by a voltage drop of the high-resistivity thin film 9; an equipotential line along the conductive rings 10, 11 exists just under the conductive rings. Accordingly, a connection line E at an edge (e) of a depletion layer is surely matched just under the conductive rings 10, 11; accordingly, an expansion step in a transverse direction of the depletion layer is ready in a step manner. That is to say, the conductive rings 10, 11 have a function to cancel a difference in expansion degrees in the transverse direction at the edge of the depletion layer; the difference does not become large until a breakdown state is caused; accordingly, it is possible to suppress an irregularity in a breakdown strength. |
