Patent ID: 9379132
Filing Date: 2016-06-28
CPC Classification: H01L

Claim Text:
1. A method of fabricating a memory device, comprising: forming a material layer stack over a major surface of a semiconductor substrate; etching the stack through a mask to the semiconductor substrate using a first etching process to form a memory opening having a sidewall defined at least in part by the stack and a bottom surface that is defined by the semiconductor substrate; etching through the memory opening using a second etching process that is different from the first etching process to remove a damaged portion of the semiconductor substrate from the bottom surface of the memory opening; forming a single crystal semiconductor material over the semiconductor substrate on the bottom surface of the memory opening using an epitaxial growth process; forming at least one memory film on at least a portion of the sidewall of the memory opening and over the single crystal semiconductor material on the bottom surface of the memory opening; forming a layer of semiconductor material over the at least one memory film on at least a portion of the sidewall of the memory opening and on the bottom surface of the memory opening; etching through the memory opening using a third etching process to remove a portion of the layer of semiconductor material and a portion of the at least one memory film from over the bottom surface of the memory opening and expose the single crystal semiconductor material on the bottom surface of the memory opening; and forming a semiconductor channel material over the layer of semiconductor material on the sidewall of the memory opening and over the single crystal semiconductor material on the bottom surface of the memory opening, wherein: forming the layer of semiconductor material comprises forming a layer of polycrystalline or amorphous semiconductor material; forming the semiconductor channel material comprises forming a single crystal semiconductor layer of channel material over the layer of polycrystalline or amorphous semiconductor material; the single crystal semiconductor layer of channel material is formed by epitaxial growth from the single crystal semiconductor material exposed on the bottom surface of the memory opening; etching through the memory opening to remove a portion of the layer of polycrystalline or amorphous semiconductor material and a portion of the at least one memory film from over the bottom surface of the memory opening comprises forming a generally cylindrically-shaped opening through the layer of polycrystalline or amorphous semiconductor material and the at least one memory film; the generally cylindrically-shaped opening comprises a sidewall defined by the layer of polycrystalline or amorphous semiconductor material and the at least one memory film and a bottom surface that is defined by the single crystal semiconductor material exposed on the bottom surface of the memory opening; forming the single crystal semiconductor layer of channel material comprises: the first, second and third portions of the layer of channel material are formed under conditions that provide a higher growth rate of epitaxial single crystal semiconductor material than a growth rate of the layer of polycrystalline or amorphous semiconductor material.