Structure for confining the switching current in phase memory (PCM) cells

US7488967B2 · kind B2 · utility

Assignee

• International Business Machines Corporation · US

Inventors

• Geoffrey Burr · Cupertino, US
• Chung H. Lam · Williston, US
• Simone Raoux · New York, US
• Stephen M. Rossnagel · Pleasantville, US
• Alejandro G. Schrott · New York, US
• Jonathan Zanhung Sun · Shrub Oak, US
• Hemantha K. Wickramasinghe · Chappaqua, US

Key dates

• Filing date: Apr 6, 2005
• Grant date: Feb 10, 2009
• Expiry date: Oct 13, 2025

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10N70/8828

Abstract

Disclosed are a phase change memory cell and a method of forming the memory cell. The memory cell comprises a main body of phase change material connected directly to a bottom contact and via a narrow channel of phase change material to a top contact. The channel is tapered from the top contact towards the main body. A minimum width of the channel has a less than minimum lithographic dimension and is narrower than a width of the main body. Therefore, the channel provides a confined region for the switching current path and restricts phase changing to within the channel. In addition an embodiment of the memory cell isolates the main body of phase change material by providing a space between the phase change material and the cell walls. The space allows the phase change material to expand and contract and also limits heat dissipation.