US Patent 9129859 Three dimensional memory structure

A method to fabricate a three dimensional memory structure includes forming an array stack, creating a layer of sacrificial material above the array stack, etching a hole through the layer of sacrificial material and the array stack, creating a pillar of semiconductor material in the hole to form at least two vertically stacked flash memory cells that use the pillar as a common body, removing at least some of the layer of sacrificial material around the pillar to expose a portion of the pillar, and forming a field effect transistor (FET) using the portion of the pillar as the body of the FET.