Three dimensional NAND string memory devices and methods of fabrication thereof

摘要

A method includes forming an amorphous or polycrystalline semiconductor material over at least a portion of a sidewall of a front side opening and within front side recesses in a stack of alternating first and second material layers, forming a layer of a metal material over at least a portion of the sidewall of the front side opening and adjacent to the semiconductor material within the front side recesses; annealing the metal material and the semiconductor material within the front side recesses to form a large grain polycrystalline or single crystal semiconductor material charge storage region within each of the front side recesses by a metal induced crystallization process, and forming a tunnel dielectric layer and semiconductor channel in the front side opening. Following the metal induced crystallization process, at least a portion of the metal material is located between the charge storage regions and the second material layers.

主权项

1. A method of making a monolithic three dimensional NAND string, comprising:
forming a stack of alternating layers of a first material and a second material different than the first material over a substrate; etching the stack to form a front side opening in the stack having a sidewall defined at least partially by the alternating layers of the first material and the second material; removing a first portion of the second material layers through the front side opening to form front side recesses between the first material layers; forming an amorphous or polycrystalline semiconductor material over at least a portion of the sidewall of the front side opening and within the front side recesses; forming a layer of a metal material over at least a portion of the sidewall of the front side opening and adjacent to the amorphous or polycrystalline semiconductor material within the front side recesses; annealing the metal material and the amorphous or polycrystalline semiconductor material within the front side recesses to form a large grain polycrystalline or single crystal semiconductor material charge storage region within each of the front side recesses by a metal induced crystallization process, wherein following the metal induced crystallization process at least a portion of the metal material is located between the charge storage regions and the second material layers; forming a tunnel dielectric layer over the charge storage regions in the front side opening; and forming a semiconductor channel over the tunnel dielectric layer in the front side opening.