Method 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 magnetoresistive device, said method comprising:
forming an oxide layer;
forming a plurality of magnetoresistive device layers above said oxide layer;
forming an etch stop above said magnetoresistive device layers;
surrounding said magnetoresistive device layers with an oxygen barrier; and
etching into said oxide layer while said magnetoresistive device layers are surrounded by said oxygen barrier.
2. The method of claim 1 , wherein said oxide layer comprises silicon oxide.
3. The method of claim 2 , wherein said oxygen barrier comprises a photoresist layer.
4. The method of claim 3 , wherein said oxygen barrier further comprises a silicon nitride layer.
5. The method of claim 1 , wherein forming a plurality of magnetoresistive device layers comprises:
forming at least one ferromagnetic layer.
6. The method of claim 1 , wherein forming a plurality of magnetoresistive device layers comprises:
forming a plurality of ferromagnetic layers; and
forming at least one nonmagnetic layer.
7. The method of claim 6 , wherein said magnetoresistive device layers comprise a spin valve.
8. The method of claim 6 , wherein said magnetoresistive device layers comprise a pseudo spin valve.
9. The method of claim 1 , wherein said etch stop comprises titanium nitride.
10. The method of claim 1 , wherein etching into said oxide layer comprises:
etching into said oxide layer to expose at least one electrical contact.
11. The method of claim 10 , further comprising:
removing at least part of said oxygen barrier; and
forming at least one electrically conductive path between said magnetoresistive device layers and said at least one electrical contact.