| 摘要 |
PURPOSE: A semiconductor device is provided to reduce manufacturing cost and improve a static noise margin by forming different threshold voltage between MOS transistors. CONSTITUTION: The semiconductor device comprises a plurality of access transistors(A1,A2) and a plurality of driver transistors(D1,D2). Drain regions of the access transistor(A1) formed on a silicon substrate(1) are n- and n+ type drain regions(6a,8a), and source regions are n- and n+ source regions(6b,8b). Source regions of the driver transistor(D1) are n- and n++ source regions(6c,10), and drain regions are n- and n+ drain regions(6b,8b). The n++ source region(10) of the driver transistor(D1) has a deep depth compared to the n+ drain region(8b), thereby increasing the static noise margin of the semiconductor devices.
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