Bottom electrode for MRAM applications
AssigneeInternational Business Machines Corporation
InventorsPrasad Bhosale, Raghuveer R. Patlolla, Michael Rizzolo, Chih-Chao Yang
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Abstract
A substantially flat bottom electrode for magnetoresistive random access memory (MRAM) devices includes three components: a recessed bulk conductive material such as copper, a conductive liner lining the recess, and a cap layer, wherein the conductive liner is a harder material than the cap layer. The cap layer and the dielectric layer are coplanar having a height differential of less than 3 nanometers. The conductive liner has a lower chemical mechanical planarization removal rate. Also provided are processes for forming the bottom electrode.
Claims20
A magnetoresistive random access memory (MRAM) device, comprising:
- a bottom electrode embedded within a dielectric layer, the bottom electrode comprising a recessed metal conductor, a conductive liner lining a recess defined by the recessed metal conductor, and a cap material filling the recess to provide a top surface coplanar to a top surface of the dielectric layer having a height differential between the top surfaces of the cap layer and the dielectric layer of less than about 3 nanometers, wherein the conductive liner has a hardness greater than the cap layer;
- a magnetic tunnel junction (MTJ) stack on the bottom electrode;
- and
- a top electrode on the MTJ stack.
A magnetoresistive random access memory (MRAM) device, comprising:
- a bottom electrode embedded within a dielectric layer, the bottom electrode comprising a recessed metal conductor, a ruthenium conductive liner lining a recess defined by the recessed metal conductor, and a tantalum nitride cap material filling the recess to provide a top surface coplanar to a top surface of the dielectric layer having a height differential between the top surfaces of the tantalum nitride and the dielectric layer of less than about 3 nanometers;
- a magnetic tunnel junction (MTJ) stack is disposed on the bottom electrode;
- and
- a top electrode is disposed on the MTJ stack.
A process of forming a bottom electrode in a magnetoresistive random access memory (MRAM) device, the process comprising:
- forming a recessed metal conductor in a dielectric layer;
- conformally depositing a conductive liner material in a recess of the recessed metal conductor and the dielectric layer;
- depositing a tantalum nitride cap layer in the recess on the conductive liner material and on the dielectric layer;
- and
- polishing the tantalum nitride cap layer to the dielectric layer with a chemical mechanical planarization process, wherein a height differential between the tantalum nitride surface remaining in the recess and the dielectric layer surface is less than 3 nanometers, wherein the conductive liner material is harder than the tantalum nitride.
Dependencies are inferred from the claim text.