METHOD FOR FABRICATING FLASH MEMORY

摘要

PURPOSE: A method for fabricating a flash memory is provided to reduce the number of fabrication processes by forming a low-voltage transistor and a high-voltage transistor of a peripheral circuit region with the same DDD(Double Doped Drain) structure. CONSTITUTION: An isolation layer is formed on a substrate(302). A well region is formed on the substrate by performing a well ion implantation process and a threshold voltage ion implantation process. A gate is formed thereon. A mask is formed on a main cell region to open a peripheral circuit region. A low-density junction region(314,316) is formed by implanting ions into a high-voltage region and a low-voltage region. A spacer(318,320) is formed on a sidewall of the high-voltage region and the low-voltage region. A mask is formed on the main cell region to open the peripheral circuit region. A high-density junction region(322,324) is formed by implanting the ions into the high-voltage region and the low-voltage region.