Vertical Thin Film Transistor Selection Devices And Methods Of Fabrication

摘要

Three-dimensional (3D) non-volatile memory arrays having a vertically-oriented thin film transistor (TFT) select device and method of fabricating such a memory are described. The vertically-oriented TFT may be used as a vertical bit line selection device to couple a global bit line to a vertical bit line. A select device pillar includes a body and upper and lower source/drain regions. At least one gate is separated horizontally from the select device pillar by a gate dielectric. Beneath each gate, a single gap fill dielectric layer extends vertically from a lower surface of the gate, at least partially separating the gate from the underlying global bit line. Between horizontally adjacent pillars, this same dielectric layer extends from its same lower level beneath the gates vertically to a level of the upper source/drain region.

主权项

1. A non-volatile storage system, comprising:
a global bit line; a first vertical thin film transistor (TFT) select device above a substrate and coupled to the global bit line, the first vertical TFT select device including a first gate that is separated from a first body by a gate dielectric, the first body extends vertically relative to the substrate, the first gate having a lower surface; a second vertical thin film transistor (TFT) select device above the substrate and coupled to the global bit line, the second TFT select device is horizontally adjacent to the first vertical TFT select device, the second TFT select device including a second gate that is separated from a second body by the gate dielectric, the second body extends vertically relative to the substrate, the second gate has a lower surface; and a gap fill dielectric formed between the first vertical TFT select device and the second vertical TFT select device, the gap fill dielectric underlying the lower surface of the first gate and the lower surface of the second gate, the gap fill dielectric extending horizontally at least partially between the first gate and the second gate.