SBIR Phase I: Enhanced Plasma deposition Process for MgO-Based Magnetic Tunnel Junctions with 500% Magnetoresistance

This Small Business Innovation Research (SBIR) Phase I project aims to demonstrate the feasibility of fabricating high quality MgO-based magnetic tunnel junction (MTJ) devices with magnetoresistance (MR) values of over 500%, via an innovative process which utilizes optimized plasma-based magnetron sputtering and RF plasma oxidation. We will use a number of novel methods to fabricate highly symmetrical, near epitaxial MgO barriers with (001)-orientation using plasma sputtering and oxidation methods. Using these methods, we will be able to realize a smoother barrier and the resulting process will be suitable for adaptation to large-scale production with high yield and uniformity. Our method combines three innovations. First, we will design a new deposition procedure to make symmetrical interfaces on both sides of the MgO barrier to enhance the coherent tunneling effect required for high MR. Secondly, we will improve the (001) texture of the MgO barrier by choosing ferromagnetic layers with a composition tuned for both high spin polarization and small lattice mismatch. Finally, we will implement a new plasma oxidation method to minimize both plasma damage to the barrier and MTJ interface roughness. If successful, the resulting MgO-based MTJ devices will surpass the performance of all other existing magnetoresistive devices. Commercially, this technology will have a huge commercial impact on the non-volatile memory specifically, for MRAM (magnetic random access memory) and disk drive for tunnel magnetoresistance (TMR) read/write heads industries. The success of the project will not only bolster the market position of MRAM and MTJ read heads, but will also enable innovative new products in other market segments, such as semiconductor failure analysis and a wide range of emerging bio-magnetic applications.