Three dimensional NAND device with birds beak containing floating gates and method of making thereof

US8987087B2 · kind B2 · utility

Assignee

• Sandisk Technologies, Inc. · US

Inventors

• Henry Chien · San Jose, US
• Donovan Lee · Santa Clara, US
• Vinod R. Purayath · Santa Clara, US
• Yuan Zhang · Nanjing, CN
• James Kai · Santa Clara, US
• George Matamis · Danville, US

Key dates

• Filing date: May 20, 2014
• Grant date: Mar 24, 2015
• Expiry date: May 20, 2034

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D88/00

Abstract

A method of making a monolithic three dimensional NAND string including forming a stack of alternating layers of a first material and a second material over a substrate. The first material comprises an electrically insulating material and the second material comprises a semiconductor or conductor material. The method also includes etching the stack to form a front side opening in the stack, forming a blocking dielectric layer over the stack of alternating layers of a first material and a second material exposed in the front side opening, forming a semiconductor or metal charge storage layer over the blocking dielectric, forming a tunnel dielectric layer over the charge storage layer, forming a semiconductor channel layer over the tunnel dielectric layer, etching the stack to form a back side opening in the stack, removing at least a portion of the first material layers and portions of the blocking dielectric layer.