METHOD OF PREPARING SPACER IN FLASH EEPROM CELL

摘要

PURPOSE: A method for forming a cell spacer is a flash EEPROM is provided to prevent reduction in the length of a gate and a coupling ratio and degradation in a breakdown voltage characteristic generated when a cell spacer is formed using a medium temperature oxide. CONSTITUTION: A method for forming a cell spacer in a flash EEPROM forms a stack gate structure in which a floating gate(304) and a control gate(306) are stacked in a selected region of a semiconductor substrate(301). An oxynitride film(312) is formed on the entire surface including the stack gate. A nitride film is formed on the oxynitride film(312). The nitride film is etched to form a spacer nitride film(309a). The exposed portion of the oxynitride film(312) is etched using the spacer nitride film(309a) as an etch mask to form a cell spacer formed of the oxynitride film(312) and the spacer nitride film(309a).