3D INDEPENDENT DOUBLE GATE FLASH MEMORY

摘要

A memory device configurable for independent double gate cells, storing multiple bits per cell includes multilayer stacks of conductive strips configured as word lines. Active pillars are disposed between pairs of first and second stacks, each active pillar comprising a vertical channel structure, a charge storage layer and an insulating layer. The insulating layer in a frustum of an active pillar contacts a first arcuate edge of a first conductive strip in a layer of the first stack and a second arcuate edge of a second conductive strip in a same layer of the second stack. A plurality of insulating columns serve, with the active pillars, to divide the stacks of word lines into even and odd lines contacting opposing even and odd sides of each active pillar. The active pillar can be generally elliptical with a major axis parallel with the first and second conductive strips.

主权项

1. A memory device, comprising:
first and second multilayer stacks of conductive strips; a plurality of active pillars between the first and second stacks, each active pillar comprising a vertical channel structure, a charge storage layer and an insulating layer, the insulating layer in a frustum of an active pillar contacting a first arcuate edge of a first conductive strip in a layer of the first stack and a second arcuate edge of a second conductive strip in a same layer of the second stack; and a plurality of inter-stack insulating columns interleaved among the plurality of active pillars between the first and second stacks.