1. Field of the Invention
The present invention relates generally to magnetoresistive (MR and GMR) sensors for read head portions of magnetic heads for hard disk drives, and more particularly to electrical leads for conducting current to such MR and GMR sensors.
2. Description of the Prior Art
In commonly used magnetoresistive (MR) and giant magnetoresistive (GMR) read head sensors an underlayer is deposited upon a wafer substrate and a first magnetic shield (S1) is fabricated upon the underlayer. A first insulation layer (G1) is then fabricated upon the S1 shield. A sensor structure is fabricated upon the G1 layer and located in a central read region of the head, while hard bias elements and electrical contact leads are fabricated and located in each of two side regions. The central sensor structure typically includes an antiferromagnetic pinning layer, ferromagnetic pinned layers, a nonmagnetic spacer layer, a ferromagnetic free layer, and a nonmagnetic cap layer. The hard bias element typically includes a seed layer and a magnetic hard bias layer. The electrical contact leads typically include a seed layer and an electrically conducting nonmagnetic lead layer. A second insulation layer (G2) followed by a second magnetic shield layer (S2) are subsequently fabricated.
A problem that has been recognized with regard to such prior art MR and GMR read heads is that the electrical leads must be thick enough to supply an adequate electrical current flow through the sensor; however, such thick electrical leads can create a rather severe step that must be covered by sufficient G2 insulation to prevent electrical shorting between the leads and the second magnetic shield S2 that is fabricated above the G2 insulation layer. It is therefore desirable to fabricate the sensor with thinner electrical leads which reduce the size of the step to avoid electrical shorting and which nevertheless conduct sufficient current to the sensor.