Patent ID: 7956423

Claim:
A semiconductor device, comprising: an insulated-gate FET (Field Effect Transistor); and an electronic element, wherein said insulated-gate FET includes: a trench gate formed in a semiconductor base; a first diffusion layer formed on a side of said trench gate; and a third diffusion layer formed in said first diffusion layer, wherein said electronic element includes: a second diffusion layer having an approximately a same impurity concentration and depth profile as said first diffusion layer; a fourth diffusion layer having an approximately a same impurity concentration and depth profile as said third diffusion layer, and formed in said second diffusion layer; a top diffusion layer, different from said fourth diffusion layer, formed in said second diffusion layer, said top diffusion layer covering an exposed area of said second diffusion layer; and a trench element-isolation layer having an approximately a same depth as said trench gate, and formed so as to surround said second diffusion layer, wherein each of said trench gate and said trench element-isolation layer includes: an insulating layer formed in a trench; and a conductive layer buried in said insulating layer.