TECHNIQUES FOR FORMING SPIN-TRANSFER TORQUE MEMORY (STTM) ELEMENTS HAVING ANNULAR CONTACTS

摘要

Techniques for forming a spin transfer torque memory (STTM) device having an annular contact to reduce critical current requirements are disclosed. These techniques reduce the critical current requirements for a given magnetic tunnel junction (MTJ), as the annular contact reduces the contact size and increases the local current density, thereby requiring to switch the direction of the free magnetic layer of the MTJ. Reduce the current. In some cases, the annular contact surrounds at least a portion of the insulator layer that prevents the passage of current. In such cases, current flows around the insulator layer through the annular contact to increase the local current density before flowing through the free magnetic layer. The insulator layer may comprise a dielectric material and, in some cases, is a tunnel material, such as magnesium oxide (MgO). In some cases, a reduction in threshold current of at least 10% is achieved for a given MTJ.