Magnetic Read Head with Magnetoresistive (MR) Enhancements Toward Low Resistance X Area (RA) Product

摘要

A method of forming a magnetoresistive (MR) sensor with a composite tunnel barrier comprised primarily of magnesium oxynitride and having a MR ratio of at least 70%, resistance x area (RA) product <1 ohm-μm2, and fewer pinholes than a conventional MgO layer is disclosed. The method involves forming a Mg/MgON/Mg, Mg/MgON/MgN, MgN/MgON/MgN, or MgN/MgON/Mg intermediate tunnel barrier stack and then annealing to drive loosely bound oxygen into adjacent layers thereby forming MgO/MgON/Mg, MgO/MgON/MgON, MgON/MgON/MgON, and MgON/MgON/MgO composite tunnel barriers, respectively, wherein oxygen content in the middle MgON layer is greater than in upper and lower MgON layers. The MgON layer in the intermediate tunnel barrier may be formed by a sputtering process followed by a natural oxidation step and has a thickness greater than the Mg and MgN layers.

主权项

1. A method of forming a magnetoresistive (MR) sensor, comprising:
(a) forming a first ferromagnetic layer; (b) depositing a first Mg layer that contacts a top surface of the first ferromagnetic layer; (c) forming a MgOyNz layer on the first Mg layer wherein y is an oxygen content and z is a nitrogen content; (d) depositing a second Mg layer or a MgN layer on the MgOyNz layer to give an intermediate tunnel barrier layer having a Mg/MgOyNz/Mg or Mg/MgOyNz/MgN configuration; (e) depositing a second ferromagnetic layer on a top surface of the intermediate tunnel barrier layer; and (f) annealing the first and second ferromagnetic layers and the intermediate tunnel barrier to give a composite tunnel barrier with a MgO/MgOy1Nz1/MgO or MgO/MgOy1Nz1/MgOy2Nz2 configuration wherein an oxygen content (y1) in the MgOy1Nz1 layer is different from an oxygen content (y2) in the MgOy2Nz2 layer, y1