MOS-Feldeffekttransistor mit hoher Durchbruchsspannung

摘要

A semiconductor device comprises a semiconductor substrate (1) of a first conductivity type, a first well (2) of a second conductivity type formed on the semiconductor substrate (1) of the first conductivity type, a first impurity diffusion layer (5) of the first conductivity type formed on the well (2) without contacting the semiconductor substrate (1), a second impurity diffusion layer (6) of the second conductivity type which surrounds the first impurity diffusion layer (5) and has an impurity concentration which is higher than that of the well (2), a third impurity diffusion layer (7) of the first conductivity type formed within the second impurity diffusion layer (6) so as to contact neither the semiconductor substrate (1) nor the first impurity diffusion layer (5), a source electrode (10) connected to both the second impurity diffusion layer (6) and the third impurity diffusion layer (7), a gate electrode (12) which is formed between the first impurity diffusion layer (5) and the third impurity diffusion layer (7) and formed on the second impurity diffusion layer (6) so as to interpose an insulation film (11) therebetween, a drain electrode (9) connected to the first impurity diffusion layer (5), and a wiring layer extracted from the drain electrode (9) outside the semiconductor substrate (1).