Novel 2-Bit/Cell Wrapped-Select-Gate SONOS TFT Memory Using Source-Side Injection for NOR-Type Flash Array

Abstract

This letter is the first to successfully demonstrate the 2-bit/cell wrapped-selected-gate (WSG) SONOS thin-film transistor (TFT) memory using source-side injection (SSI). Because of the higher programming efficiency of SSI, a memory window of approximately 3 V can be easily achieved in 10 mu s and 30 ms for the program and erase modes, respectively. In addition, we performed an excellent 2-bit/cell distinguish margin for 3-V memory window in WSG-SONOS TFT memory. The optimal reliability of the endurance and data retention tests can be executed by adjusting the applied voltage appropriately.