A study on characteristics of the scaled SONOSFET NVSM for Flash memory

플래시메모리를 위한 scaled SONOSFET NVSM 의 프로그래밍 조건과 특성에 관한 연구

  • 박희정 (광운대학교 전자재료공학과) ;
  • 박승진 (광운대학교 전자재료공학과) ;
  • 홍순혁 (광운대학교 전자재료공학과) ;
  • 남동우 (광운대학교 전자재료공학과) ;
  • 서광열 (광운대학교 전자재료공학과)
  • Published : 2000.07.01

Abstract

When charge-trap SONOS cells are used flash memory, the tunneling program/erase condition to minimize the generation of interface traps was investigated. SONOSFET NVSM cells were fabricated using 0.35$\mu\textrm{m}$ standard memory cell embedded logic process including the ONO cell process. based on retrograde twin-well, single-poly, single metal CMOS process. The thickness of ONO triple-dielectric for memory cell is tunnel oxide of 24${\AA}$, nitride of 74 ${\AA}$, blocking oxide of 25 ${\AA}$, respectively. The program mode(Vg: 7,8,9 V, Vs/Vd: -3 V, Vb: floating) and the erase mode(Vg: -4,-5,-6 V, Vs/Vd: floating, Vb: 3V) by modified Fowler-Nordheim(MFN) tunneling were used. The proposed programming condition for the flash memory of SONOSFET NVSM cells showed less degradation($\Delta$Vth, S, Gm) characteristics than channel MFN tunneling operation. Also the program inhibit conditions of unselected cell for separated source lines NOR-tyupe flash memory application were investigated. we demonstrated that the program disturb phenomenon did not occur at source/drain voltage of 1 V∼4 V and gate voltage of 0 V∼4.

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