| 摘要 |
PROBLEM TO BE SOLVED: To provide a highly reliable resistance, and to reduce the size of a semiconductor device in which a MOS transistor and a resistance element are loaded together on the same semiconductor substrate. SOLUTION: An n-type well region 11 is formed on the surface of a p-type semiconductor substrate 10, and a p-type resistance layer 20 is formed on the surface of the well region 11. A conductive layer 30 is formed to encircle the resistance layer 20 on the well region 11 in a circular manner. A pull-down resistance 2 and other elements (e.g., a p-channel MOS transistor 1) are separated by applying a predetermined voltage to the conductive layer 30 during an ordinal operation to prevent a channel from being formed under the conductive layer 30. The resistance layer 20 does not contact with an element separation insulating film. A PMOS 1 and the pull-down resistance 2 are both formed in one region encircled by the element separation insulating film. COPYRIGHT: (C)2008,JPO&INPIT
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