Nonvolatile integrated circuit memory devices having ground interconnect lattices with reduced lateral dimensions

摘要

Nonvolatile integrated circuit memory devices having ground interconnect lattices are provided to have reduced lateral dimensions because the ground interconnect lines therein occupy less total area. With respect to integrated circuit memory devices containing NAND strings of EEPROM memory cells, the ground select electrodes for respective first and second pluralities of NAND strings (on a first side of a metal ground line) are joined together so that the number of ground select electrodes crossing the metal ground line can be reduced. The area normally occupied by the crossing ground select electrodes can then be used to interconnect the metal ground line to a substrate ground line using an interconnect via. Thus, the area normally reserved exclusively for the ground interconnect vias can be reduced or eliminated altogether by reducing the number of ground select electrodes which actually cross the metal ground line. In addition, to facilitate the connection of the metal ground line to the substrate ground line, depletion-mode transistors are formed in those areas where the ground select electrode(s) crosses the substrate ground line(s). The use of depletion-mode transistors prevents the formation of an electrical "open" between the substrate ground line and the metal ground line when the ground select electrodes are unbiased.