Method of forming ultra-smooth bottom electrode surface for depositing magnetic tunnel junctions

US11374165B2 · kind B2 · utility

Assignee

• Applied Materials, Inc. · US

Inventors

• Lin Xue · San Diego, US
• Sajjad Amin Hassan · Fremont, US
• Mahendra Pakala · San Jose, US
• Jaesoo Ahn · San Jose, US

Key dates

• Filing date: Mar 5, 2020
• Grant date: Jun 28, 2022
• Expiry date: May 12, 2040

Classification

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

Abstract

A process sequence is provided to provide an ultra-smooth (0.2 nm or less) bottom electrode surface for depositing magnetic tunnel junctions thereon. In one embodiment, the sequence includes forming a bottom electrode pad through bulk layer deposition followed by patterning and etching. Oxide is then deposited over the formed bottom electrode pads and polished back to expose the bottom electrode pads. A bottom electrode buff layer is then deposited thereover following a pre-clean operation. The bottom electrode buff layer is then exposed to a chemical mechanical polishing process to improve surface roughness. An magnetic tunnel junction deposition is then performed over the bottom electrode buff layer.