| 摘要 |
PURPOSE:To prevent an error due to the displacement of a mask on the diffusion of source and drain regions by forming dummy polysilicon parallel with gate polysilicon as well as the gate polysilicon and coating the dummy polysilicon with an LOCOS oxide film. CONSTITUTION:The formation of dummy polysilicon on the edge sections of LOCOS oxide films differs from conventional structure. The LOCOS oxide film 3 are formed to an silicon substrate as a P-back gate through selective oxidation using an Si3N4 film, etc. as masks. The areas of a source region 1 and a drain region 2 (both are represented by oblique lines) take values proportional to length in the X-axis direction because length in the Y-axis direction is the same, but these values proportional to length in the X-axis direction are also made the same because spaces among the gate polysilicon 4 and the dummy polysilicon 8 regulating each side parallel with a Y axis are equal on the left and the right. Accordingly, the areas of the source region 1 and the drain region 2 can be made the same at all times even when positional displacement due to errors on mask alignment among the LOCOS oxide film 3 (dotted lines) and the gate polysilicon 4 (and the dummy polysilicon 8) is generated. |
