Micron Technology, Inc.
SOURCE/DRAIN INTEGRATION IN A THREE-NODE ACCESS DEVICE FOR VERTICAL THREE DIMENSIONAL (3D) MEMORY

Abstract:

Systems, methods and apparatus are provided for a three-node access device in vertical three dimensional (3D) memory. An example method includes a method for forming arrays of vertically stacked memory cells, having horizontally oriented access devices and vertically oriented access lines. The method includes depositing alternating layers of a dielectric material and a sacrificial material in repeating iterations to form a vertical stack. An etchant process is used to form a first vertical opening exposing vertical sidewalls in the vertical stack adjacent a first region of the sacrificial material. The first region is selectively etched to form a first horizontal opening removing the sacrificial material a first horizontal distance back from the first vertical opening. A multilayer first source/drain material, a channel material, and a second source/drain material are deposited in the first horizontal opening to form a three-node access device for a memory cell among the arrays of vertically stacked memory cells.