Semiconductor integrated circuit device having double diffusion insulated gate field effect transistor

摘要

To provide a lateral double diffusion insulated gate field effect transistor with high driving current and low source-drain withstand voltage without receiving the influence of process fluctuation. Without shortening a gate electrode 10 as compared with conventional one, an impurity of the same conductivity type as a drain is ion-implanted from the side of a high concentration drain region 20 by using the gate electrode as a mask in a self-aligning manner. The amount of impurity implantation is set as higher than the concentration of a semiconductor substrate 19.