Patent ID: 8865582
Filing Date: 2014-10-21
Classification: H01L

Abstract:
1. A method comprising: providing a substrate comprising a monocrystalline semiconductor, wherein the monocrystalline semiconductor comprises silicon; forming a thermally grown tunnel oxide layer on the substrate, wherein the thermally grown tunnel oxide layer comprises silicon dioxide; depositing a protective layer on the thermally grown tunnel oxide layer, thereby forming a stack of the thermally grown tunnel oxide layer and the protective layer on the substrate, wherein the protective layer comprises polycrystalline silicon; forming at least one opening in the stack, thereby exposing at least one portion of the substrate; cleaning the at least one exposed portion with a cleaning liquid, wherein the protective layer is substantially unaffected by the cleaning liquid; loading the substrate comprising the stack into an epitaxial reactor; thereafter, performing an in-situ etch to remove the protective layer, wherein the etch is selective with respect to the thermally grown tunnel oxide layer; using the at least one exposed portion as a source to epitaxially grow a layer comprising the monocrystalline semiconductor material; and forming the layer comprising the monocrystalline semiconductor material into at least two columnar floating gate structures by: thermally growing an oxide layer on sidewalls of the at least two columnar floating gate structures; and thereafter, depositing a control gate layer between and on top of the at least two columnar floating gate structures.