发明授权
- 专利标题: Multiple level flash memory
- 专利标题(中): 多级闪存
-
申请号: US09680651申请日: 2000-10-06
-
公开(公告)号: US06275417B1公开(公告)日: 2001-08-14
- 发明人: Peter W. Lee , Fu-Chang Hsu , Hsing-Ya Tsao
- 申请人: Peter W. Lee , Fu-Chang Hsu , Hsing-Ya Tsao
- 主分类号: G11C1604
- IPC分类号: G11C1604
摘要:
Data stored in multi-level memory cells is rapidly read out with high resolution by generating and coupling a predetermined and preferably low number of large magnitude jump-like voltage changes to the control gates of the memory cells. The magnitude of the jumps can be a substantial fraction of the power supply level and will be many times the &Dgr;Vt levels associated with the memory cells, e.g., the control gate voltage changes in jump-steps from say 4 V to 6 V to 8 V. Use of a low number of jump-steps (e.g., two or three) reduces read out time by permitting read out of a plurality of Vt levels during a given control voltage magnitude. Further, use of large but different magnitude control gate voltages provides good read out resolution over the range of Vt values. Reference cells are provided to improve tracking, and DRAM-type sense amplifiers are provided to maintain high noise immunity.