| 摘要 |
PURPOSE:To provide a well region and an element region isolated sufficiently from each other and still suitable for fine construction of a device, by forming a recess in a part of a semiconductor substrate having MOSFET source and drain region and a well region formed on the surface thereof such that the recess is deeper than the source and drain region or the well region, and providing MOS transistors on the top surface around the recess and on the bottom of the recess, respectively, while providing an insulation region on the side wall of the recess. CONSTITUTION:After a P-type well region 22 is formed on the surface of an N-type semiconductor substrate 21, a recess 23 is formed deeper than the well region 22. An oxide film 24 is deposited on the surface of the semiconductor substrate 21 and the well region 22, including the recess 23. The oxide film 25 is then removed from the side walls of the recess 23 by etching. A gate electrode 26 of an N-channel MOSFET and an N-type diffusion layer 27 providing source and drain regions are provided on the surface of the P-type well region 22. On the other hand, a gate electrode 28 of a P-channel MOSFET and a P-type diffusion layer 29 are provided on the surface of the N-type semiconductor substrate 21 on the bottom of the recess 23. |
