| 摘要 |
In an LDMOS, an n-type region 6, which is formed to have a concentration higher than that of an n-type substrate 1 and whose concentration gradually increases from the n-type substrate 1 to an n+ type drain region 5, is disposed so as to surround the n+-type drain region 5. Further, a p+-type contact region 9 disposed adjacent to an n+-type source region 8 is formed so as to extend below the n+-type source region 8 so that a parasitic transistor formed by the n+-type source region 8, a p-type base region 7 and the n-type substrate 1 is hardly turned ON. |
