| 摘要 |
PROBLEM TO BE SOLVED: To increase cell density and decrease ON resistance by composing a drain take-out region with a trench drain region that is formed from the surface of a well region to a buried region and a first diffusion drain region where the width becomes narrower from the surface of the buried region to the trench drain region. SOLUTION: An N+-type buried region 2002 is formed on a silicon substrate 2001, and an N-type well region 2003 is formed on it. From the surface, the section of an N+-type trench drain region that is made of polysilicon is formed in a square so that it does not reach the N+-type buried region 2002. Then, an N+-type first diffusion drain region 102 is formed so that it covers the lower portion of the N+-type trench drain region, and at the same time touches the N+-type buried region 2002. Also, a region that is not surrounded by the N+-type first diffusion drain region 102 out of the outer-periphery surface of the N+-type trench drain region is surrounded by an N+-type second diffusion drain region 103. |
