Memory structure having a magnetic tunnel junction (MTJ) self-aligned to a T-shaped bottom electrode, and method of manufacturing the same

US10069064B1 · kind B1 · utility

Assignee

• Headway Technologies, Inc. · US

Inventors

• Jesmin Haq · Milpitas, US
• Tom Zhong · Saratoga, US
• Zhongjian Teng · Santa Clara, US

Key dates

• Filing date: Jul 18, 2017
• Grant date: Sep 4, 2018
• Expiry date: Jul 18, 2037

Classification

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

Abstract

A process flow for forming a magnetic tunnel junction (MTJ) cell that is self-aligned to an underlying bottom electrode (BE) is disclosed. The BE is comprised of a lower BE layer having a first width (w1), and an upper (second) BE layer with a second width (w2) where w2>w1. Preferably, the BE has a T shape. A stack of MTJ layers including an uppermost hard mask is deposited on the BE and has width w2 because of a self-aligned deposition process. A dummy MTJ stack is also formed around the first BE layer. An ion beam etch where ions are at an incident angle <90° with respect to the substrate is used to remove extraneous material on the sidewall. Thereafter, an encapsulation layer is deposited to insulate the MTJ cell, and to fill a gap between the first BE layer and dummy MTJ stack.