A 20 ns 1 Mb CMOS burst mode EPROM

A 64-K*16-b burst-mode EPROM (electrically programmable read-only memory) with a 20-ns statistical access time was achieved using 1.4- mu m lithography. An orthogonal x-drive and split array architecture allows efficient array segmentation utilizing a contactless buried diffusion memory cell. The resultant die size is 54.6 mm/sup 2/. The contactless, buried-diffusion memory cell is constructed using a self-aligned thick oxide (SATO) process which minimizes the array dimensions by requiring diffusion contacts only every 16 bits. The SATO array can be continuously biased without a power penalty because of its virtual ground array configuration. In many system applications, the burst mode memory configuration offers performance approaching maximum processor capability.<>