| abstract |
A semiconductor device includes a p − -silicon substrate, n − -epitaxial growth layers on the p − -silicon substrate, a field insulating film at the surface of the n − -epitaxial growth layer, an npn transistor formed at the n − -epitaxial growth layer, an pnp transistor formed at the n − -epitaxial growth layer, a DMOS transistor on the n − -epitaxial growth layer, and a resistance. The DMOS transistor includes an n + -diffusion layer forming a source, a p-type diffusion layer forming a back gate region, a lightly doped n-type diffusion layer forming a drain, and a heavily doped n + -diffusion layer forming the drain. |