Analog floating-gate capacitor with improved data retention in a silicided integrated circuit

US8779550B2 · kind B2 · utility

Assignee

• TEXAS INSTRUMENTS INCORPORATED · US

Inventors

• Kaiping Liu · Plano, US
• Amitava Chatterjee · Plano, US
• Imran Khan · Richardson, US

Key dates

• Filing date: Jun 27, 2012
• Grant date: Jul 15, 2014
• Expiry date: Jun 27, 2032

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D84/811

Abstract

An analog floating-gate electrode in an integrated circuit, and method of fabricating the same, in which trapped charge can be stored for long durations. The analog floating-gate electrode is formed in a polycrystalline silicon gate level, and includes portions serving as a transistor gate electrode, a plate of a metal-to-poly storage capacitor, and a plate of poly-to-active tunneling capacitors. A silicide-block film comprised of a layer of silicon dioxide underlying a top layer of silicon nitride blocks the formation of silicide cladding on the electrode, while other polysilicon structures in the integrated circuit, such as polysilicon-to-metal capacitors, are silicide-clad. Following silicidation, a capacitor dielectric is deposited over the remaining polysilicon structures, followed by formation of an upper metal plate.