| 摘要 |
PURPOSE:To constitute a high withstanding-voltage element by the area of the irreducible minimum of a demand, and to reduce leakage by determining the proper bias of a field plate while monitoring the extent of a depletion layer. CONSTITUTION:An N type substrate 11 as a collector, a P type layer 12 as a base and a P type layer 13 constituting another element are formed, and field plates 16, 17 for increasing the withstanding voltage of the section (a transistor) of the P type layer 12 and the section of the P type layer 13 are shaped. Monitor electrodes 183, 184 and 193, 194 for a depletion layer 14 are formed, the changes of electric resistance among both electrodes are monitored in response to the extent of the depletion layer 14, and proper biases are applicated to field plates 185, 195, thus optimally controlling the elongation of the depletion layer 14. A channel with the adjacent P type layer 13 can be cut, and the elongation of the depletion layer is inhibited and leakage can be reduced within an operating range where withstanding voltage is not needed more than required. |
