MANUFACTURE OF NONVOLATILE SEMICONDUCTOR MEMORY

摘要: PURPOSE:To prevent erroneous erasing from a drain side at the time of reading/ writing by varying thickness gate insulating film under floating in longitudinal direction channel, and increasing first film. CONSTITUTION:An element isolating region is formed on surface P-type silicon substrate 11, 12, second 13 are its active substrate. In this case, since 12 additionally oxidized, it becomes thicker than 13. Then, polysilicon layer 14 formed, patterned to be extended films 13, third 15 further thereon, control electrode 16 patterned. Thereafter, 15, etched remaining used as electrode. Thus, reading/writing can prevented.