Structure and method for forming a body contact for vertical transistor cells

US6593612B2 · kind B2 · utility

Assignee

• Infineon Technologies AG · DE

Inventors

• Ulrike Gruening · Wappingers Falls, US
• Helmut Klose · Munich, DE
• Wolfgang Bergner · Waldbüttelbrunn, DE

Key dates

• Filing date: Dec 5, 2000
• Grant date: Jul 15, 2003
• Expiry date: Dec 25, 2020

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10B12/0385

Abstract

A semiconductor memory cell, in accordance with the present invention includes a deep trench formed in a substrate. The deep trench includes a storage node in a lower portion of the deep trench, and a gate conductor formed in an upper portion of the deep trench. The gate conductor is electrically isolated from the storage node. An active area is formed adjacent to the deep trench and is formed in the substrate to provide a channel region of an access transistor of the memory cell. A buried strap is formed to electrically connect the storage node to the active area when the gate conductor is activated. A body contact is formed opposite the deep trench in the active area and corresponding in position to the buried strap to prevent floating body effects due to outdiffusion of the buried strap. Methods for forming the body contact are also described.