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

A memory array comprising:

• a semiconductive substrate;
• a plurality of conductive data/bit lines extending generally in a first direction and formed in an upper surface of the substrate;
• a plurality of access transistors extending generally upward from the upper surface of the substrate and aligned generally atop a corresponding data/bit line, wherein the access transistors comprise:
• a pillar extending generally upward from the upper surface of the substrate and generally aligned atop the corresponding data/bit line wherein a source region is formed generally at a lower portion of the pillar so as to be in electrical communication with the corresponding data/bit line and a drain region is formed generally at an upper portion of the pillar, wherein the pillar intermediate the source and drain regions is substantially fully depleted;
• and
• a gate structure substantially about the pillar in lateral directions such that the access transistors are substantially off with no applied gate potential;
• and
• a plurality of conductive word lines extending generally in a second direction and in electrical contact with a corresponding gate structure at least a first surface thereof such that bias voltage applied to a given word line is communicated about the corresponding pillar via the gate structure.