Three-dimensional memory device with horizontal silicon channels and method of making the same

Abstract

A vertically alternating sequence of multi-fingered silicon-germanium layers and multi-fingered silicon layers is formed over a substrate. The multi-fingered silicon-germanium layers include silicon-germanium wires, and the multi-fingered silicon layers include silicon wires. Tubular memory films and multi-fingered gate electrodes are formed. Each gate electrode includes a respective gate electrode bar which overlies the silicon wires and a respective set of vertically-extending gate electrode fingers which is adjoined to a bottom portion of the respective gate electrode bar and spaced apart by the silicon wires. The multi-fingered silicon-germanium layers are removed selective to multi-fingered silicon layers. First active regions are formed at an end portion of each of the silicon wires. Second active regions are formed on silicon plate portions of the multi-fingered silicon layers.