A 60nm NOR Flash Memory Cell Technology Utilizing Back Bias Assisted Band-to-Band Tunneling Induced Hot-Electron Injection (B4-Flash)

A p-channel SONOS flash memory cell technology, which provides excellent scalability and high programming efficiency for NOR architecture, has been developed. The cells named B4-Flash utilizing novel back bias assisted band-to-band tunneling induced hot-electron (B4-HE) injection is proposed. By applying a moderate back bias to the cell during programming, the bit-line voltage can be reduced below the supply voltage, 1.8V. Resulting that the B4-Flash, applicable to NOR architecture, achieves the gate length of 60nm, for the first time. Basic operation of the 50nm B4-Flash cell is also confirmed. Proposed B4-HE injection scheme realizes not only extreme scalability but also high programming efficiency for NOR type cell