Semiconductor device and method of manufacturing the same

摘要

A semiconductor substrate made of P-type silicon is formed with two MOS transistors having a first gate electrode and a second gate electrode placed in parallel with each other. A first N-type impurity drain diffusion layer and a second N-type impurity source diffusion layer are connected in series between the first and second gate electrodes. A first high-concentration P-type impurity diffusion layer for threshold control is formed in a source-side portion of a channel region of the semiconductor substrate underlying a portion of the first gate electrode closer to the first N-type impurity source diffusion layer, while a second high-concentration P-type impurity diffusion layer for threshold control is formed under a portion of the second gate electrode closer to the second N-type impurity source diffusion layer.