| 摘要 |
<p>A semiconductor device according to embodiments of the invention includes an n−-type drift region; a p-type base region formed selectively in the surface portion of the drift region; an n+-type emitter region and a p+-type body region, both formed selectively in the surface portion of base region; and an n-type shell region between the drift region and the base region, a shell region surrounding the entire region below base region. The shell region is doped more heavily than the drift region. The shell region contains an n-type impurity at an effective impurity amount of 8.0×1011 cm−2 or smaller. A drift region exhibits a resistivity low enough to prevent the depletion layer expanding from collector region, formed on the back surface of the drift region, toward a shell region from reaching the shell region.</p> |
