A Novel Gate-Injection Program/Erase P-Channel NAND-Type Flash Memory with High (10M 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 SONOS (BE-SONOS), 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 (10 M 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.