Method of utilizing fabrication process of floating gate spacer to build twin-bit monos/sonos memory

摘要

The present invention discloses a method of utilizing the fabrication process of floating gate spacer to build a twin-bit MONOS/SONOS memory, wherein recessed ONO spacers are used to fabricate a discontinuous floating gate below a poly control gate to obtain a MONOS/SONOS memory device having twinbit memory cells. Cross talk between charges stored in the two bits can be avoided, hence enhancing the reliability of memory device. Moreover, if the voltage Vt varies during the fabrication process, the device can restore its normal characteristics through the individual and separate characteristic of the two bits and by using program or erase condition. The present invention can utilize the fabrication process of ONO spacer to complete the fabrication process of floating gate in automatic alignment way without the need of undergoing several mask processes.