Memory with offset bank select cells at opposite ends of buried diffusion lines

Abstract

A compact contactless Flash memory architecture has memory cells instead of isolation regions between adjacent diffused lines in rows of a bank and thereby increases the density of memory cells in the bank when compared to prior architectures. Diffused lines in the bank can be used as virtual ground lines or as bit lines depending on which column of the bank is selected for access. The architecture includes about half as many metal lines as diffused lines, and most bank select cells operate to connect respective metal lines to respective pairs of diffused lines.