纳米尺度自旋转移矩器件的制备工艺

Fabrication Process of the Nano-Scale Spin Transfer Torque Device

提出一种改进的自旋转移矩器件的制备工艺:在电子束曝光形成纳米级图形之后,依次采用离子束刻蚀、带胶绝缘层淀积再正胶剥离的图形转移方法,成功制备了纳米柱状赝自旋阀结构磁性多层膜CoFe/Cu/CoFe/Ta,器件的横向尺寸为140nm×70nm。对该结构进行了电磁学性质的测试:在变化范围为-500～+500Oe(1A/m=4π×10-3 Oe)的外加磁场下,观测到巨磁阻效应;在零外加磁场下,施加垂直于膜平面的电流时,观测到电流诱导的磁化翻转效应,其临界电流密度为108 A/cm2量级。该方法具有工艺步骤少、易于实现的特点,在自旋转移矩器件等纳米级器件的制备中具有广泛的应用前景。

An improved fabrication process of spin transfer torque devices was presented.After nanoscale graphics formed by the electron beam lithography,the magnetic multilayer film CoFe/Cu/CoFe/Ta with nanopillar pseudo-spin-valve structure was successfully fabricated by ion beam etching,isolation layer deposition with photoresist and lift-off successively,and its transverse size was 140 nm×70 nm.The electronic and magnetic characteristics tests of the structure were conducted.The giant magnetic resistor（GMR） effect was observed when the externally applied magnetic field was from-500 to ＋500 Oe（1 A/m=4π×10-3 Oe）.The current-induced magnetization switching（CIMS） effect was observed when a current vertical was applied to the film plane at the zero externally applied magnetic field,and the critical current density of the magnetization switching was 108 A/cm2.The proposed process has advantages of less steps and easy realization,therefore it has a broad prospect of application in the fabrication of nano-scale devices such as the spin transfer torque devices.