Longitudinal sensor bias structures and method of formation thereof
The present disclosure generally relates to a storage device comprising soft bias structures having high coercivity and high anisotropy, and a method of forming thereof. The soft bias structures may be formed by moving a wafer in a first direction under a plume of NiFe to deposit a first NiFe layer at a first angle, moving the wafer in a second direction anti-parallel to the first direction to deposit a second NiFe layer at a second angle on the first NiFe layer, and repeating one or more times. The soft bias structures may be formed by rotating a wafer to a first position, depositing a first NiFe layer at a first angle, rotating the wafer to a second position, depositing a second NiFe layer at a second angle on the first NiFe layer, and repeating one or more times. The first and second NiFe layers have different grain structures.
1. A method of forming soft bias structures, comprising:
moving a wafer a first direction under a plume of NiFe to deposit a first NiFe layer on a surface of the wafer, the first NiFe layer being deposited at a first angle with respect to the surface of the wafer; and
moving the wafer a second direction opposite the first direction under the plume of NiFe to deposit a second NiFe layer on the first NiFe layer, the second NiFe layer being deposited at a second angle with respect to the surface of the wafer.
2. The method of claim 1 , further comprising:
repeating moving the wafer under the plume of NiFe alternatingly in the first direction and the second direction one or more times to deposit one or more additional NiFe layers on the second NiFe layers.
3. The method of claim 1 , wherein the first angle and the second angle are between about 5° to about 30° with respect to the surface of the wafer.
4. The method of claim 1 , wherein the first angle and the second angle are the same.
5. The method of claim 1 , wherein the first and second NiFe layers each comprises Ni 80 Fe 20 or Ni 45 Fe 55 .
6. The method of claim 1 , wherein the first NiFe layer and the second NiFe layer have different grain structures.
7. The method of claim 1 , wherein the soft bias structures are formed adjacent to a magnetic read sensor.