| 摘要 |
PURPOSE:To eliminate the deterioration in the characteristics of a semiconductor device even if the device is broken down by applying a reverse bias between the emitter and the base of the device by forming the center of the emitter region of high impurity density region higher than the periphery thereof. CONSTITUTION:A P type base region 4 is formed at the center in the surface layer of an N type Si substrate 6, and an N type emitter region 3 is formed at the center in the surface layer of the region 4. Further, an N<+> type high density region 7 higher than the periphery is formed at the center of the region 3. When plus bias is applied to an emitter electrode 1 and minus reverse bias is applied to an base electrode 2 in this transistor, depletion layers 9, 10 are expanded from P-N junction 8 as designated by arrows. In this case, the expansion of the depletion layer 10 in the region 3 is reduced, and the width (a) of the layers 9, 10 becomes narrower than the width (b) of the layers 9, 10 at the other junction 8. With the result that, no break down occurs at the surface. On the other hand, the breakdown at the center does not cause any damage for a crystal. |
