| 摘要 |
PURPOSE:To enhance the withstand voltage of a semiconductor device by oxidizing a polysilicon layer to form a gate insulating film to alleviate electic field concentration in the vicinity of a drain. CONSTITUTION:A first gate layer 14 off-set from the drain side on a gate insulating film 12 is formed thereon, and a polysilicon layer is then coated on the portion in the vicinity of the drain of the gate insulating film 12 and on the gate layer 14. The polysilicon layer is then oxidized to form an interlayer insulating and gate insulating film 20. A second gate layer 22 is then formed on the portion in the vicinity of a drain at least from the film 20. The layer 22 is then patterned, and source and drain diffusing openings are formed at the films 20 and 12, respectively, suitable doner impurity is selectively diffused through the openings in the substrate 10 to form by self-matching an N<+>-type source region 24 and an N<+>-type drain region 26 at the gate. |
