Memory array with ultra-thin etched pillar surround gate access transistors and buried data/bit lines

摘要

A memory array with data/bit lines extending generally in a first direction formed in an upper surface of a substrate and access transistors extending generally upward and aligned generally atop a corresponding data/bit line. The access transistors have a pillar extending generally upward with a source region formed so as to be in electrical communication with the corresponding data/bit line and a drain region formed generally at an upper portion of the pillar and a surround gate structure substantially completely encompassing the pillar in lateral directions and extending substantially the entire vertical extent of the pillar and word lines extending generally in a second direction and in electrical contact with a corresponding surround gate structure at at least a first surface thereof such that bias voltage applied to a given word line is communicated substantially uniformly in a laterally symmetric extent about the corresponding pillar via the surround gate structure.