Alternate metal virtual ground EPROM array implemented in a 0.8 mu m process for very high density applications

Abstract

Alternate Metal Virtual Ground EPROM array (AMG) is introduced as a new scaling concept. This array dramatically reduces cell size by making poly pitch the only limitation in both X and Y directions. The AMG concept scales cell size by sharing one metal line per two diffusion bit lines and relies on a segmentation scheme and fieldless array to achieve the poly pitch limited cell. The cell size in 0.8pm technology is 2 . 5 6~2 which is considerably smaller than standard EPROM cell in 0.6pm technology [1.2]. A major advantage of this array is reduction of drain turn-on induced punch through. This reduction allows scaling of effective channel length to as low as 0.25pm, resulting in high read current and fast programming time.

Flash memory cells-an overview

“…AMG cells [74] come as an extension of a similar AMG EPROM cell, and the cell concept is the same as the industry standard. AMG cell-size scaling is accomplished by sharing one metal line per two diffusion bit lines; a new segmentation scheme and fieldless array allow the achievement of the minimum design rule of the process, which typically is the pitch of polysilicon.…”