| 摘要 |
PURPOSE:To prevent the lowring of punch-through voltage by providing a region of high density under the source and drain regions of an enhancement type element when the enhancement type driving MOS transistor and a depression type load MOS transistor are formed on one semiconductor substrate. CONSTITUTION:On the periphery of the P<-> type Si substrate 21, thick field SiO2 films 26 for separation of element are formed with a P<+> type region 25 as an underlay thereof and between them a thin gate SiO2 film 27 is connected. Next, a resist film 28 having an opening in an enhancement (E) type MOS transistor forming region 29 is provided, a P<+> type channel region 30 is formed through the injection of ions by using the film 28 as a mask, and thus a region of higher density than the substrate 21 provided only in an E type element region. Then, the resist film 28 is renewed by a film 31, the N<-> type channel region 33 of the D type element is provided, gate electrodes 361 and 362 are fitted to respective element regions through the intermediary of the film 27, and between two elements an N<+> type region 35 is formed, while the source and drain regions 401-403 are formed in the element region. |
