Structure and method for improved isolation in trench storage cells

US6437401B1 · kind B1 · utility

Assignees

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

Inventors

• Jack A. Mandelman · Stormville, US
• Stephan Kudelka · Radeberg, DE
• Andreas Knorr · Saratoga Springs, US
• Stephen Rahn · Höhenkirchen-Siegertsbrunn, DE
• Helmut Tews · Poughkeepsie, US
• Michael Wise · Washington, US

Key dates

• Filing date: Apr 3, 2001
• Grant date: Aug 20, 2002
• Expiry date: Apr 3, 2021

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10B12/0383

Abstract

A trench capacitor structure for improved charge retention and method of manufacturing thereof are provided. A trench is formed in a p-type conductivity semiconductor substrate. An isolation collar is located in an upper portion of the trench. The substrate adjacent the upper portion of the trench contains a first n+ type conductivity region and a second n+ type conductivity region. These regions each abut a wall of the trench and are separated vertically by a portion of the p-type conductivity semiconductor substrate. A void which encircles the perimeter of the trench is formed into the wall of the trench and is located in the substrate between the first and second n+ type conductivity regions.