Trench capacitor and method for fabricating the trench capacitor

US6987295B2 · kind B2 · utility

Assignee

• Infineon Technologies AG · DE

Inventors

• Bernhard Sell · Dresden, DE
• Annette Sanger · Dresden, DE
• Dirk Schumann · Lübbenau/Spreewald - Lubnjow/Błota, DE

Key dates

• Filing date: Aug 28, 2003
• Grant date: Jan 17, 2006
• Expiry date: Aug 28, 2023

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D86/201

Abstract

A trench capacitor for use in a DRAM memory cell contains a lower capacitor electrode, a storage dielectric, and an upper capacitor electrode, which are at least partially disposed in a trench. The lower capacitor electrode adjoins, in a lower trench region, a wall of the trench, while in the upper trench region there is a spacer layer that adjoins a wall of the trench and is made from an insulating material. The upper electrode contains at least three layers, a first layer disposed in the trench on the storage dielectric and containing doped polysilicon, a second layer disposed on the first layer and containing metal-silicide, and a third layer disposed on the second layer and containing doped polysilicon. The layers of the upper electrode in each case extending along the walls and the base of the trench up to at least the upper edge of the spacer layer.