| 摘要 |
PURPOSE:To increase withstanding voltage by forming a drain of double structure consisting of a high concentration region and a low concentration region surrounding the former. CONSTITUTION:An N-region 12 is formed on a pi substrate 11 and then a P<+> region 13 which becomes a base region is formed. An N<+> region 14 which becomes a source region is formed using the same window used when forming the P<+> region 13. At the same time, an N<+> region 15 which becomes a drain region is formed. By surrounding the high concentration drain region 15 with a low concentration N<-> layer 12, the concentration of a part between the drain 15 and a junction face is decreased, and further, by decreasing the concentration gradient of the low concentration region between the drain 15 and the junction face, the with-standing voltage of the drain can be increased without forming the drain region 5 deeply. |
