Patent ID: 9659955
Date: 2017-05-23
CPC Classifications: H01L

Claim:
1. A method of forming a device, comprising: forming an alternating stack of insulating layers and sacrificial material layers over a substrate; forming a memory opening extending through the alternating stack; forming an aluminum oxide layer directly on sidewall surfaces of the sacrificial material layers and directly on sidewall surfaces of the insulating layers after formation of the memory opening within a volume of the memory opening, such that first aluminum oxide portions of the aluminum oxide layer are located on sidewall surfaces of the sacrificial material layers, and second aluminum oxide portions of the aluminum oxide layer are located on sidewalls of the insulating layers; and removing the second aluminum oxide portions at a greater etch rate than the first aluminum oxide portions employing a selective etch process, wherein all or a predominant portion of each first aluminum oxide portion remains after removal of the second aluminum oxide portions.