SEMICONDUCTOR DEVICE AND MANUFACTURING METHOD THEREOF

摘要

PROBLEM TO BE SOLVED: To enable to reduce a sheet resistance value of a drain region of an MOS transistor. SOLUTION: In this semiconductor device, two n-type epitaxial layers 4, 5 are formed on a p-type single crystal silicon substrate 3. An n-type buried diffusion layer 20 to be used as the drain region is exposed from a rear surface 49 of the substrate 3. A metal layer 50 contacting the buried diffusion layer 20 is formed on the rear surface 49 side of the substrate 3. This structure enables the metal layer 50 to be used as the drain region, and can remarkably reduce the sheet resistance value in the drain region. COPYRIGHT: (C)2007,JPO&INPIT