FABRICATION METHOD OF FLASH MEMORY DEVICE

摘要

PURPOSE: A fabrication method of flash memory device is provided to form a trench and then form floating gates on both sides of the trench, thereby solving prior problems. CONSTITUTION: A fabrication method of flash memory device comprises steps of: forming a trench of prescribed depth on a substrate and then forming a tunnel oxide film on the substrate; forming a polysilicon layer on the tunnel oxide film and then etching the polysilicon layer and the tunnel oxide film until the substrate is exposed, thereby forming floating gates on both sides of the trench; injecting impurity ions into the exposed substrate to form first and second bonding areas and then forming a dielectric film on overall structure; and removing the dielectric film and then depositing polysilicon to form control gates.