| 摘要 |
PROBLEM TO BE SOLVED: To reduce the chip size and improve the heat radiation property in a semiconductor device having a plurality of transistors.SOLUTION: A high-side transistor 300 and a low-side transistor 301 each consisting of a horizontal type NMOSFET are formed on a semiconductor layer 205. In the high-side transistor 300, a source region 22 surrounds a drain region 23. In the low-side transistor 301, a drain region 23 surrounds a source region 22. Further, a semiconductor device is configured so that a P-type well diffusion layer 20 of the high-side transistor reaches an SOI substrate, and so that the P-type well diffusion layer and a drain drift region 206 of the low-side transistor have a part contacted by PN junction and are short-circuited by a common electrode.SELECTED DRAWING: Figure 2 |
