TUNNELING MAGNETORESISTANCE (TMR) READ SENSOR WITH LOW-CONTACT-RESISTANCE INTERFACES

摘要

The invention provides a TMR read sensor with low-contact-resistance metal/metal, metal/oxide and oxide/metal interfaces. The low-contact-resistance metal/metal interfaces in a reference or sense layer structure are in-situ formed in a high-vacuum deposition module of a sputtering system, without exposures to low vacuum in a transfer module and damages caused by a plasma treatment conducted in an etching module. The low-contact-resistance metal/oxide interface is formed by utilizing a thin Co—Fe—B reference layer and a thick Co—Fe reference layer to reduce boron diffusion and segregation caused by annealing. The low-contact-resistance oxide/metal interface is formed by replacing a Co—Fe—B sense layer with a Co-rich Co—Fe sense layer to eliminate boron diffusion and segregation caused by annealing. With the low-contact-resistance metal/metal, metal/oxide and oxide/metal interfaces, the TMR read sensor exhibits a junction resistance-area product of below 0.6 Ω-μm², while maintaining a low ferromagnetic coupling field and a high TMR coefficient.