Low resistance strap for high density trench DRAMS

US6503798B1 · kind B1 · utility

Assignees

• International Business Machines Corporation · US
• Kabushiki Kaisha Toshiba · JP

Inventors

• Ramachandra Divakaruni · Ossining, US
• Jeffrey P. Gambino · Gresham, US
• Herbert L. Ho · New Windsor, US
• Akira Sudo · Poughkeepsie, US

Key dates

• Filing date: Jun 30, 2000
• Grant date: Jan 7, 2003
• Expiry date: Dec 13, 2020

Classification

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

Abstract

A method and structure for a dynamic random access device which includes a substrate having a trench, a conductor in the trench, a transistor adjacent the trench and a conductive strap electrically connecting the conductor and the transistor, wherein the strap comprises a plurality of strap conductors and the strap has a lower resistance than the conductor. The conductor comprises a first material having a first resistance and the strap comprises a second material different than the first material having a second resistance, wherein the second resistance is lower than the first resistance. The plurality of strap conductors comprises at least two electrically connected strap conductors, and a first strap conductor is adjacent the conductor and a second strap conductor is adjacent the transistor and the first strap conductor has an improved interface with the conductor. The strap comprises a lip strap, wherein the strap forms an L-shape. At least one of the plurality of the strap conductors is contiguous with a corner of the trench, and the plurality of strap conductors comprises a first strap conductor and a second strap conductor and the conductor is contiguous with the first strap…