Magnetic tunnel junction memory and method with etch-stop layer

US7445943B2 · kind B2 · utility

Assignee

• Everspin Technologies, Inc. · US

Inventors

• Kenneth Smith · Chandler, US
• Brian R. Butcher · Gilbert, US
• Gregory W. Grynkewich · Gilbert, US
• Srinivas V. Pietambaram · Gilbert, US
• Nicholas Rizzo · Gilbert, US

Key dates

• Filing date: Oct 19, 2006
• Grant date: Nov 4, 2008
• Expiry date: Feb 20, 2027

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10N50/01

Abstract

Methods and apparatus are provided for magnetoresistive memories employing magnetic tunnel junction (MTJ). The apparatus comprises a MTJ (61, 231), first (60, 220) and second (66, 236) electrodes coupled, respectively, to first (62, 232) and second (64, 234) magnetic layers of the MTJ (61, 231), first (54, 204) and second (92, 260) write conductors magnetically coupled to the MTJ (61, 231) and spaced apart from the first (60, 220) and second (66, 236) electrodes, and at least one etch-stop layer (82, 216) located between the first write conductor (54, 204) and the first electrode (60, 220), having an etch rate in a reagent for etching the MTJ (61, 231) and/or the first electrode (60, 220) that is at most 25% of the etch rate of the MTJ (61, 231) and/or first conductor (60, 220) to the same reagent, so as to allow portions of the MTJ (61, 231) and first electrode (60, 220) to be removed without affecting the underlying first write conductor (54, 204). In a further embodiment, a second etch-stop layer (90, 250) is located between the second electrode (66, 236) and the second write conductor (92, 260). Improved yield and performance are obtained.