Programmable read-only memory formed with opposing PN diodes

摘要

A semiconductor PROM contains a group of PROM cells (12) each consisting of a pair of opposing diodes oriented vertically with their common intermediate region (22 and 24) fully adjoining a recessed oxide insulating region (16). The PN junction (30) of the upper diode of each pair lies in non-monocrystalline semiconductor material. A composite buried layer consisting of buried regions (32) which adjoin the insulating region below the lower cell regions (20) and a buried web (44) which laterally surrounds each buried region is employed to improve programming efficiency as well as provide intermediate electrical connections.