Thin-film storage transistors in a 3-dimensional array of nor memory strings and process for fabricating the same

Abstract

A thin-film storage transistor formed in a memory array above a planar surface of a semiconductor substrate, includes (a) first and second planar dielectric layers, each being substantially parallel the planar surface of the semiconductor substrate; (b) a first semiconductor layer of a first conductivity having an opening therein; (c) second and third semiconductor layers of a second conductivity type opposite the first conductivity type, located on two opposite sides of the first semiconductor layer; (d) a charge-storage layer provided in the opening adjacent and in contact with the first semiconductor layer; and (e) a first conductor provided in the opening separated from the first semiconductor layer by the charge storage layer, wherein the first, second and third semiconductor layers are each provided as a planar layer of materials between the first and second dielectric layers. In this configuration, the first, second and third semiconductor layers and the first conductor provide a channel region, a drain region, a source region and a gate electrode of the thin-film storage transistor.