Formation of self-aligned buried strap connector

US6579759B1 · kind B1 · utility

Assignees

• International Business Machines Corporation · US
• Infineon Technologies AG · DE

Inventors

• Michael P. Chudzik · Beacon, US
• Jochen Beintner · Wappingers Falls, US
• Ramachandra Divakaruni · Ossining, US
• Rajarao Jammy · Hopewell Junction, US

Key dates

• Filing date: Aug 23, 2002
• Grant date: Jun 17, 2003
• Expiry date: Aug 23, 2022

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D1/047

Abstract

In a vertical-transistor DRAM cell, the problem of making a reliable electrical connection between the node of the deep trench capacitor and the lower electrode of the vertical transistor is solved by; depositing a temporary insulator layer, forming a vertical spacer on the trench walls above the temporary insulator, then stripping the insulator to expose the substrate walls; diffusing dopant into the substrate walls to form a self-aligned extension of the buried strap; depositing the final gate insulator; and then forming the upper portion of the DRAM cell.