Method of preparing buried LOCOS collar in trench DRAMS

US6599798B2 · kind B2 · utility

Assignee

• Infineon Technologies AG · DE

Inventors

• Helmut Tews · Poughkeepsie, US
• Stephan Kudelka · Radeberg, DE
• Uwe Schroeder · Fishkill, US
• Rolf Weis · Dresden, DE

Key dates

• Filing date: Jul 24, 2001
• Grant date: Jul 29, 2003
• Expiry date: Jul 24, 2021

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10B12/0385
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

The vertical DRAM capacitor with a buried LOCOS collar characterized by: a self-aligned bottle and gas phase doping; no consumption of silicon at the depth of the buried strap; no reduction of trench diameter; and a nitride layer to protect trench sidewalls during gas phase doping.