20-Mb/s erase/record flash memory by asymmetrical operation

An asymmetrical recording and erasing operation of Flash memory is proposed where the threshold voltage of erase and record states are set above the thermal equilibrium threshold voltage. The recording rate is made ten times faster by using this method along with two other proposed methods: accurate control of the fastest bit and continuous recording using two memory banks. The erasing rate is also made ten times faster by using large-scale parallel operation made practical by a proposed multiphase word-driving scheme. These proposed circuit technologies will enable 20-Mb/s erase/record Flash memories for use in personal high-definition television (HDTV) movie cameras.