| 摘要 |
PURPOSE:To reduce the difference of threshold voltages of narrow and wide channel MISFETs by controlling the threshold voltage to the prescribed value by the sum of the first impurity doped for regulating the voltage, the second impurity laterally diffused in case of forming a channel stopper, and the third impurity of a reverse conductive type to the second impurity. CONSTITUTION:A thin SiO2 film 2 is formed on an N<-> type silicon substrate 1, and Si3N4 film patterns 4a, 4b and 4c are individually formed to coat N-type wide channel, P-type wide and N-type narrow channel MOSFET forming regions 3a, 3b, 3c. After ions are selectively implanted through the patterns 4a, 4c and the film 2, a P<-> type well 5 is formed. B<+>-implanted region 107 and P<+>-implanted region 108 are activated and redistributed to form P-type and N-type channel stoppers 7, 8 under a field oxide film 9. A resist mask 11 is formed on the region 3c, and phosphorus (P<+>) ions are selectively implanted to form a compensating P<+>-implanted region.
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