METHOD OF MANUFACTURING A SEMICONDUCTOR MEMORY DEVICE

摘要

A method for fabricating a semiconductor memory device is provided to prevent generation of TED(Transient Enhanced Diffusion) and to stabilize a threshold voltage by removing a point defect generated in a high voltage NMOS transistor DDD(Double Doped Drain) ion-implantation process by a DRA(Damage Recovery Anneal) process. Wells for forming a channel and adjusting a threshold voltage are sequentially formed on a semiconductor substrate(101). A stacked gate is formed on the semiconductor substrate. A DDD mask pattern is formed at an interval of a predetermined length with the gate. Ions are implanted into the semiconductor substrate between the gate and the DDD mask pattern to form a DDD junction. A defect of the semiconductor substrate caused by the ion implantation is removed by a heat treatment to remove a point defect.