| 摘要 |
PURPOSE:To enhance yield, reliability and mass-productivity, by encircling the side surfaces and bottom surface of a second semiconductor region, which surrounds the source region and the drain region of a sensor FET, by a first semiconductor region. CONSTITUTION:A second silicon semiconductor substrate 21 having a second conductive type semiconductor region 23 is prepared on a first conductive type semiconductor region 22 and an N<+> type diffusion region 24 is subsequently formed. In the next step, a first P<+> type channel stopper region 25 is formed in a ring form within a second semiconductor region and, succeedingly, an N<+> type source region is formed in a ring form within a second semiconductor region 23a while an N<+> type drain region 27 is simultaneously formed. Thereafter, a second P<+> type channel stopper region 28 is provided and, succeedingly, an SiO2 membrane 29, an Si3N4 membrane and an SiO2 membrane 33 are successively formed in the region surrounded by the broken line in the drawing while a protective insulating membrane 33 is formed to a part of the surface of the substrate 21. A source electrode 35 is formed so as to reach the upper surface of the second semiconductor region 23a to connect a bulk and a source. At last, a dot line position is cut to complete an indivisual sensor FET. |
