Method for fabricating magnetoresistive read head having a bias structure with at least one dusting layer

1. A method of fabricating a bias structure of a magnetoresistive read head comprising a magnetoresistive sensor stack formed on a substrate, comprising:

forming an underlayer;

forming a bias layer over the underlayer; and

forming a dusting layer directly below at least one of the underlayer or the bias layer,

wherein the dusting layer is between the bias layer and the magnetoresistive sensor stack, and the dusting layer comprises discontinuous, nano-sized islands,

wherein the dusting layer is formed of a dusting layer material that has a melting temperature that is higher than a melting temperature of the underlayer.

2. The method of claim 1 , wherein forming the underlayer comprises depositing an underlayer material by ion-beam deposition.

3. The method of claim 1 , wherein forming the bias layer comprises depositing a bias layer material by ion-beam deposition.

4. The method of claim 1 , wherein forming the dusting layer comprises depositing a dusting layer material by ion-beam deposition.

5. The method of claim 4 , wherein depositing the dusting layer material is performed prior to forming the underlayer.

6. The method of claim 4 , wherein the dusting layer material is deposited at a rate of approximately 0.3 to 0.7 Angstroms per second.

7. The method of claim 6 , wherein depositing the dusting layer material is performed for a time period having a duration ranging from approximately 2 seconds to approximately 30 seconds.

8. The method of claim 4 , wherein depositing the dusting layer material is performed after forming the underlayer and prior to forming the bias layer.

9. The method of claim 1 , wherein the underlayer layer is formed to have grain sizes less than approximately 150 Angstroms.

10. The method of claim 1 , wherein the underlayer is formed to have a thickness less than 170 Angstroms.

11. The method of claim 10 , wherein the underlayer layer is formed to have grain sizes of approximately 100-110 Angstroms.

12. The method of claim 10 , wherein the bias layer is formed to have grain sizes of approximately 100-110 Angstroms.

13. A method of fabricating a bias structure of a magnetoresistive read head comprising a magnetoresistive sensor stack formed on a substrate, comprising:

forming an underlayer;

forming a bias layer over the underlayer; and

forming a dusting layer directly below at least one of the underlayer or the bias layer;

wherein the dusting layer is between the bias layer and the magnetoresistive sensor stack, and the dusting layer comprises discontinuous, nano-sized islands and,

wherein the dusting layer is formed of a dusting layer material that comprises a material selected from the group consisting of tungsten, tantalum, niobium, rhodium, molybdenum, tungsten-titanium alloy, tungsten-chromium alloy, nickel-aluminum alloy, platinum, and titanium.

14. The method of claim 13 , wherein the dusting layer is formed to have a thickness less than approximately 10 Angstroms.

15. The method of claim 14 , wherein the dusting layer is formed to have a thickness in the range of approximately 2 Angstroms to approximately 6 Angstroms.

16. A method of fabricating a bias structure of a magnetoresistive read head comprising a magnetoresistive sensor stack formed on a substrate, comprising:

forming an underlayer;

forming a bias layer over the underlayer; and

forming a dusting layer directly below at least one of the underlayer or the bias layer,

wherein the dusting layer is between the bias layer and the magnetoresistive sensor stack, and the dusting layer comprises discontinuous, nano-sized islands and,

wherein the dusting layer is formed of a dusting layer material that has a melting temperature that is higher than 1800° C.