SEMICONDUCTOR DEVICE AND MANUFACTURING METHOD THEREOF

摘要

PROBLEM TO BE SOLVED: To enable to reduce a sheet resistance value in a collector region by coupling first and second buried diffusion layers. SOLUTION: In this semiconductor device, two n-type epitaxial layers 5, 6 are formed on a p-type single crystal silicon substrate 4. An n-type buried diffusion layer 21 to be used as the collector region is exposed from a rear surface 56 of the substrate 4. A metal layer 57 contacting the n-type buried diffusion layer 21 is formed on the rear surface 56 side of the substrate. This structure enables the metal layer 57 to be used as the collector region, and can remarkably reduce the sheet resistance value in the collector region. COPYRIGHT: (C)2007,JPO&INPIT