METHOD FOR FORMING TUNNEL OXIDE LAYER OF NONVOLATILE SEMICONDUCTOR MEMORY DEVICE

摘要

PURPOSE: A method for forming a tunnel oxide layer of a nonvolatile semiconductor memory device is provided to be capable of increasing coupling ratio by reducing the surface of the tunnel oxide layer. CONSTITUTION: A gate oxide layer(22) is formed on a semiconductor substrate(20). A photoresist pattern is formed on the gate oxide layer(22) for exposing the predetermined portion of the gate oxide layer(22). A sacrificial oxide layer is formed on the resultant structure. An opening portion is formed in the gate oxide layer(22) by carrying out a wet etching process using the photoresist pattern as a mask. A tunnel oxide layer(28) is formed in the bottom portion of the opening portion. Preferably, the sacrificial oxide layer is formed by carrying out a CVD(Chemical Vapor Deposition) process at the temperature of 150-200 °C.