Hitachi Global Storage Technologies Netherlands B.v.

Dulip Ajantha Welipitiya

Brian Rodrick York

Thomas E Shatz

Wen-yaung Lee

Ben Long Thai

A tunnel junction TMR magnetoresistive sensor formed on layers having nitrogen interspersed therein. The nitrogenation of the layers on which the sensor is deposited allows the sensor layers to have very smooth, uniform surfaces. This greatly improves sensor performance by, for example, providing a very uniform barrier layer thickness.

TMR sensor having an under-layer treated with nitrogen for increased magnetoresistance

A magnetoresistive sensor having a Ta cap layer with nitrogen added in situ during deposition. The nitrogen in the cap layer can be formed by depositing a Ta cap layer in a sputter deposition chamber having a small amount of nitrogen in an Ar atmosphere. The resulting nitrogenated cap layer exhibits reduced specular scattering, which results in improved magnetic performance of the magnetoresistive sensor.

GMR sensor having a capping layer treated with nitrogen for increased magnetoresistance

A method for controlling magnetostriction in a free layer of a magnetoresistive sensor. A pinned layer structure is deposited and then a spacer layer, preferably Cu is deposited. Oxygen is introduced into the spacer layer. The oxygen can be introduced either during the deposition of the spacer layer or after the spacer layer has been deposited. A free layer structure is then deposited over the spacer layer. A capping layer such as Ta can be deposited over the free layer structure. The sensor is annealed to set the magnetization of the pinned layer. In the process of annealing the sensor the oxygen migrates out of the spacer. After annealing, no significant amount of oxygen is present in either the spacer layer or the free layer structure, and only trace amounts of oxygen are present in the Ta capping layer. Although no Oxygen remains in either the spacer layer or the free layer, the introduction of oxygen during manufacture causes the finished free layer to have a lower magnetostriction (ie greater negative magnetostriction).

Method for controlling magnetostriction in a free layer of a magnetoresistive sensor

A magnetoresistive sensor having a substrate that has been treated with nitrogen (nitrogenated). The nitrogenated substrate includes an alumina base layer and a thin top layer of crystalline alumina that has had a very small amount of nitrogen deposited on top. The amount of nitrogen deposited on top of the alumina is less than or equal to two monolayer, and is preferably less than on monolayer. The amount of nitrogen deposited on top of the alumina substrate is not enough to constitute a layer of nitrogen, but affects the structure of the alumina to cause the alumina to have a desired crystalline structure and an extremely smooth surface.

GMR sensor having an under-layer treated with nitrogen for increased magnetoresistance

A magnetoresistive sensor having a substrate that has been treated with nitrogen (nitrogenated) and having a Ta cap layer with nitrogen added in situ during deposition. The nitrogenated substrate includes an alumina base layer and a thin top layer of crystalline alumina that has had a very small amount of nitrogen deposited on top. The amount of nitrogen deposited on top of the alumina is less than or equal to two monolayer, and is preferably less than on monolayer. The amount of nitrogen deposited on top of the alumina substrate is riot enough to constitute a layer of nitrogen, but affects the structure of the alumina to cause the alumina to have a desired crystalline structure and an extremely smooth surface. The nitrogen in the cap layer can be formed by depositing a Ta cap layer in a sputter deposition chamber having a small amount of nitrogen in an Ar atmosphere.

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Morgan Hill, CA, United States of America

Dulip Ajantha Welipitiya