| 摘要 |
PURPOSE:To prevent concentration of an electric current only in the vicinity of a gate arc electrode in a thyristor at arcing time by specifying the width of low net- like impurity layer operating as a current control terminal of the thyristor to special value. CONSTITUTION:Net-like pattern P<++> type buried layers 2, 31-33, 41-44 are radially formed at the P2 layer of a thyristor having P1 layer, N1 layer, P2 layer and N2 layer excluding the central portion. In this case, the width t in a direction requiring the expansion of conducting direction is set less than 300mu, and the width w in a direction considering with no expansion of the conducting region is equal to the width t or larger. When the width t exceeds 300mu, the exapnsion of the arcing current in the direction as designated by an arrow 11 is obstructed to increase the voltage drop thereat and to lower the turn-off enable current. That is, the conducting area is not almost expanded in a direction as designated by an arrow 12 having, for example a width of 400mu at the low resistance buried layer, but less than 300mu, the conducting area is easily increased in width in a direction as designated by an arrow 11. |
