Electrical Characterization of Sub-micron Magnetic Tunneling Junction Cells Using Scanning Probe Microscopy

Abstract

We attempted to measure the tunneling current behavior of magnetic tunneling junction (MTJ) cells utilizing scanning probe microscopy (SPM) interfaced with an external magnetic field generator. Magnetic field was generated by allowing current to flow through coils and controlled by current ieldfeedback circuit, thereby enabling the evaluation of tunneling current under various magnetic fields. I-V measurement was carried out in the contact mode using a conducting cantilever at a specific magnetic field. The obtained magnetoresistance (MR) ratios of MTJ cells were about 21% regardless of the variation in the size of MTJ cells, and RA ranged from 8.5 K to 12.5 K[Ωµm2]. In addition, we also attempted to observe magnetic images of MTJ cells under various magnetic fields. We believe that the novel characterization method utilizing SPM is greatly beneficial for the characterization of MTJ cells because it enables the measurement of the I-V behavior of ultrasmall cells without the need for a using an extra electrode. Thus, the novel method may be used to measure the electrical properties of ultrasmall MTJ cells, namely below 0.1 µm×0.1 µm.