Performance of Co/Al2O3/NiFe magnetic tunnel junctions prepared by a two-step rf plasma oxidation method

A two-step rf plasma oxidation technique of an insulating layer has been pe rformed to enhance electrical and structural properties of magnetic tunnel junction (MTJ) devices. Comparison was made by analyzing properties of the MTJ oxidized by conventional rf and two-step rf plasma oxidation methods. E xperimentally observed results give improved surface imaging and sufficient oxygen contents of the insulating layer under the two-step oxidation metho d. In addition, electrical breakdown voltage and magnetoresistance of the M TJ were increased from 0.7 to 1.8 V and from 4.5% to 6.8%, respectively, co rrelated with improved structural information. (C) 2001 American Institute of Physics.