A new write/erase method for the reduction of the stress-inducedleakage current based on the deactivation of step tunneling sites forflash memories

摘要

This paper describes a new write/erase method to improve the readdisturb characteristics by means of drastically reducing thestress-induced leakage current in the tunnel oxide. With the proposedwrite/erase method, the degradation of the read disturb life time after106 write/erase cycles can be drastically reduced to 50% incomparison with the conventional bipolarity write/erase method. Thefeatures of the proposed write/erase method are as follows: (1) applyingan additional pulse to the control gate just after completion of thewrite/erase operation; (2) the voltage of the additional pulse is higherthan that of the control gate in a read operation, and lower than thatof the control gate in a write operation; and (3) the polarity of thevoltage is the same as that of the control gate voltage in the readoperation. This proposed write/erase method is based on the deactivationmechanism of the leakage current, which is discussed in detail in thispaper