Semiconductor element with electric field reducing device mounted therein for increasing dielectric strength

摘要

Expansion promotion means (24) for more efficiently promoting the expansion of the depletion layer (19) than the electrically insulating film(14) having a suppressor electrode layer (20) buried therein is arranged between narrow portions (23b) of the suppressor electrode layer to control the expansion of the depletion layer (19), by which arrangement the spacing s between the narrow portions (23b) can be reduced without decreasing the field reducing effect of the field reduction means, which contains the suppressor electrode layer.