| 摘要 |
<p>A semiconductor device having a high withstand voltage separation structure formed from a double RESURF structure is provided with the high withstand voltage separation structure that separates a low-potential region and a high-potential region. The high withstand voltage separation structure has an annular band-shaped planar shape and is configured from straight-line portions and corner portions each connected to the straight-line portions. In the high withstand voltage separation structure, a p-type RESURF region is formed along the outer periphery of an n-type well region on the surface layer on the substrate front side of the n-type well region. By making the total impurity amount per unit area of the RESURF region smaller in the corner portion than in the straight-line portion, the position (32a) of a dose amount at which the peak value of the withstand voltage curve (32) in the corner portion is obtained can match the position (31a) of a dose amount at which the peak value of the withstand voltage (31) in the straight-line portion is obtained. As a result, the element withstand voltage can be increased, thereby making it possible to suppress reduction in element withstand voltage due to process variations.</p> |
