Method for forming three-dimensional memory device with sacrificial channels

Abstract

In certain aspects, a first opening extending vertically through a first dielectric deck including a first plurality of interleaved sacrificial layers and dielectric layers above a substrate is formed. A high-k dielectric layer and a channel sacrificial layer free of polysilicon are subsequently formed along a sidewall of the first opening. A second opening extending vertically through a second dielectric deck including a second plurality of interleaved sacrificial layers and dielectric layers on the first dielectric deck is formed to expose the channel sacrificial layer in the first opening. The channel sacrificial layer is removed in the first opening. A memory film and a semiconductor channel are subsequently formed over the high-k dielectric layer along sidewalls of the first and second openings.