A novel gate-injection program/erase p-channel NAND-type flash memory with high (10 m cycle) endurance

We have successfully developed a novel nitride-trapping non-volatile memory device using gate injection for program and erase operations. The device is a p-channel bandgap-engineered SONGS (BE-SONGS) [1], but with ultra-thin ONO tunneling dielectric grown on top of the trapping nitride. Programming and erasing are by -FN electron injection and +FN hole injection from the poly gate, respectively. Since gate oxide is not used as the tunnel dielectric, it is spared of the program/erase current stressing, thus causes much less interface state generation after P/E cycling stressing. Very high endurance (10M cycle P/E) is achieved owing to suppressed channel interface (S.S. and gm) degradation. Moreover, due to the gate injection instead of channel injection this novel device is insensitive to STI bird's beak geometry. Successful p-channel NAND array characteristics including the program inhibit and reading characteristics are demonstrated.