Integrated circuit trench device with a dielectric collar stack, and method of forming thereof

US6486024B1 · kind B1 · utility

Assignee

• Infineon Technologies AG · DE

Inventors

• Helmut Tews · Poughkeepsie, US
• Alexander Michaelis · Wappingers Falls, US
• Stephan Kudelka · Radeberg, DE
• Uwe Schroeder · Fishkill, US
• Ulrike Gruening · Wappingers Falls, US

Key dates

• Filing date: May 24, 2000
• Grant date: Nov 26, 2002
• Expiry date: May 24, 2020

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10B12/038

Abstract

A method of using at least two insulative layers to form the isolation collar of a trench device, and the device formed therefrom. The first layer is preferably an oxide (e.g., silicon dioxide 116) formed on the trench substrate sidewalls, and is formed through a TEOS, LOCOS, or combined TEOS/LOCOS process. Preferably, both the TEOS process and the LOCOS process are used to form the first layer. The second layer is preferably a silicon nitride layer (114) formed on the oxide layer. The multiple layers function as an isolation collar stack for the trench. The dopant penetration barrier properties of the second layer permit the dielectric collar stack to be used as a self aligned mask for subsequent buried plate (120) doping.