Methods for fabricating giant magnetoresistive (GMR) devices
In a method of fabricating a giant magnetoresistive (GMR) device a plurality of magnetoresistive device layers is deposited on a first silicon nitride layer formed on a silicon oxide layer. An etch stop is formed on the magnetoresistive device layers, and a second layer of silicon nitride is formed on the etch stop. The magnetoresistive device layers are patterned to define a plurality of magnetic bits having sidewalls. The second silicon nitride layer is patterned to define electrical contact portions on the etch stop in each magnetic bit. The sidewalls of the magnetic bits are covered with a photoresist layer. A reactive ion etch (RIE) process is used to etch into the first silicon nitride and silicon oxide layers to expose electrical contacts. The photoresist layer and silicon nitride layers protect the magnetoresistive layers from exposure to oxygen during the etching into the silicon oxide layer.
1. A method of fabrication for a giant magnetoresistive (GMR) device, said method comprising:
forming a silicon oxide layer;
forming a first silicon nitride layer on said silicon oxide layer;
forming a plurality of GMR device layers on said first silicon nitride layer, said GMR device layers including a plurality of ferromagnetic layers and a nonmagnetic layer;
forming an etch stop on said GMR device layers;
forming a second silicon nitride layer on said etch stop;
patterning said GMR device layers to define sidewalls of said GMR device layers;
patterning said second silicon nitride layer to expose a portion of said etch stop;
covering said sidewalls of said GMR device layers with a photoresist layer;
while said sidewalls of said GMR device layers are covered by said photoresist layer, etching into said first silicon nitride layer and into said silicon oxide layer to expose at least one electrical contact.
2. The method of claim 1 , further comprising:
removing said photoresist layer; and
forming at least one electrically conductive path between said GMR device layers and said at least one electrical contact.
3. The method of claim 1 , wherein said GMR device layers comprise a spin valve.
4. The method of claim 1 , wherein said GMR device layers comprise a pseudo spin valve.
5. The method of claim 1 , wherein said etch stop comprises titanium nitride.