Method of forming nitridated tunnel oxide barriers for flash memory technology circuitry and STI and LOCOS isolation

摘要

An improved flash memory device, which has shallow trench isolation in the periphery region and LOCOS isolation in the core region is provided. A hard mask is used first to create the shallow trench isolation. The LOCOS isolation is then created. Subsequent etching is used to remove stringers. The flash memory is able to use shallow trench isolation to limit encroachment. The flash memory may also have a nitridated tunnel oxide layer. A hard mask is used to prevent nitride contamination of the gate oxide layer.