Method for making a current-perpendicular-to-the-plane (CPP) magnetoresistive (MR) sensor with reduced-width self-aligned top electrode

摘要

A method for making a current-perpendicular-to-the-plane magnetoresistive sensor structure produces a top electrode that is “self-aligned” on the top of the sensor and with a width less than the sensor trackwidth. A pair of walls of ion-milling resistant material are fabricated to a predetermined height above the biasing layers at the sensor side edges. A layer of electrode material is then deposited onto the top of the sensor between the two walls. The walls serve as a mask during angled ion milling to remove outer portions of the electrode layer. The height of the walls and the angle of ion milling determines the width of the resulting top electrode. This leaves the reduced-width top electrode located on the sensor. Because of the directional ion milling using walls that are aligned with the sensor side edges, the reduced-width top electrode is self-aligned in the center of the sensor.

主权项

1. A method for making a magnetoresistive sensor structure, the structure including a substrate, a sensor stack on the substrate and having a width and side edges, an isolation layer adjacent each sensor stack side edge and a ferromagnetic biasing layer adjacent each isolation layer, the method comprising;
forming on each biasing layer a wall of ion-milling resistant material whereby the sensor stack is located between said two walls; depositing on the sensor stack in the region between said two walls a layer of electrode material; ion milling the layer of electrode material, at an acute angle relative to the layer of electrode material, using a first of said two walls as a mask, to remove a portion of said electrode layer adjacent the second of said two walls; and ion milling the layer of electrode material, at an acute angle relative to the layer of electrode material, using the second of said two walls as a mask, to remove a portion of said electrode layer adjacent the first of said two walls, whereby the electrode layer has a width less than the width of the sensor stack.