| 摘要 |
PROBLEM TO BE SOLVED: To provide a simulation method for quickly and accurately analyzing the dielectric breakdown protective resistance of a dielectric breakdown protective circuit. SOLUTION: A dielectric breakdown protective element constituted of an insulation gate type field effect transistor is replaced with an equivalent circuit using a bipolar transistor, and a current flowing from the drain of the dielectric breakdown protective element to a substrate is expressed by a first current source by an impact ionization current and a second current source by the current based on an electron / hole pair thermally generated in a depletion layer. The first current source is expressed by the product of a drain current in the case without impact ionization, a coefficient accompanying the impact ionization and a function for adjustment. The function for the adjustment is fixed when a drain voltage is smaller than a prescribed value and decreases when the drain voltage is larger than the prescribed value. With the first and second current sources as input, circuit simulation is repeatedly executed until desired dielectric breakdown protective resistance is obtained while changing the function for the adjustment. COPYRIGHT: (C)2005,JPO&NCIPI
|
