READ ONLY MEMORY WRITABLE ELECTRICALLY

摘要

PURPOSE:To effectively evade anxiety increasing a write time and occurring defective read due to leakage current flowing into the floating gate of a non- selective cell in an electrically writable read only memory. CONSTITUTION:The memory array of a flash EEPROM 1 is separated to k pieces of segments SG in a row direction, and respective segments SG1-SGk are selected by a segment selection signal Xk and a memory cell M in the selected segment is selected by supplying the AND of the segment selection signal Xk and control gate control voltages WL1-WLn. Thus, only one segment SG among plural segments SG1-SGn is selected.