A 98 mm2 die size 3.3-V 64-Mb flash memory with FN-NOR type four-level cell. - Masayoshi Ohkawa; Hiroshi Sugawara; Naoaki Sudo; Masaru Tsukiji; Ken-ichiro Nakagawa; Masato Kawata; Ken-ichi Oyama; Toshio Takeshima; Shuichi Ohya (IEEE J. Solid State Circuits, 1996)