Three-dimensional memory devices and fabricating methods thereof

US11469248B2 · kind B2 · utility

Assignee

• YANGTZE MEMORY TECHNOLOGIES CO., LTD. · CN

Inventors

• Lei Ding · Plano, US
• Jing Gao · 红钢城街道, CN
• Chuan Yang · Chongqing, CN
• Lan Yu · Beijing, CN
• Ping Yan · Nanhu, CN
• Sen Zhang · 安丰镇, CN
• Bo Xu · Beijing, CN

Key dates

• Filing date: Dec 4, 2020
• Grant date: Oct 11, 2022
• Expiry date: Dec 4, 2040

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10B43/35

Abstract

A three-dimensional (3D) NAND memory device is provided. The device comprises an alternating stack including a plurality of dielectric/conductive layer pairs each comprising a dielectric layer and a conductive layer. The device further comprises a conductive wall vertically penetrating through the alternating stack and extending in a horizontal direction, and a spacer layer on sidewalls of the conductive wall configured to insulate the conductive wall from the conductive layers of the alternating stack. The spacer layer comprises a first spacer sublayer having a first dielectric material, a second spacer sublayer having a second dielectric material, and a third spacer sublayer having a third dielectric material. The second spacer is sandwiched between the first spacer sublayer and the third spacer sublayer. A second k-value of the second dielectric material is higher than a first k-value of the first dielectric material and higher than a third k-value of the third dielectric material.