Method of MRAM fabrication with zero electrical shorting

US7936027B2 · kind B2 · utility

Assignee

• MagIC Technologies, Inc. · US

Inventors

• Rongfu Xiao · Dublin, US
• Chyu-Jiuh Torng · Pleasanton, US
• Tom Zhong · Saratoga, US
• Witold Kula · Gilroy, US

Key dates

• Filing date: Jan 7, 2008
• Grant date: May 3, 2011
• Expiry date: Nov 3, 2029

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10N50/10

Abstract

An MTJ cell without footings and free from electrical short-circuits across a tunneling barrier layer is formed by using a Ta hard mask layer and a combination of etches. A first etch patterns the Ta hard mask, while a second etch uses O2 applied in a single high power process at two successive different power levels. A first power level of between approximately 200 W and 500 W removes BARC, photoresist and Ta residue from the first etch, the second power level, between approximately 400 W and 600 W continues an etch of the stack layers and forms a protective oxide around the etched sides of the stack. Finally, an etch using a carbon, hydrogen and oxygen gas completes the etch while the oxide layer protects the cell from short-circuits across the lateral edges of the barrier layer.