【摘要】 利用金属掩模法优化了制备磁性隧道结的实验和工艺条件,金属掩模的狭缝宽度为100μm.采用4nm厚的Co75Fe25为铁磁电极和1·0或0·8nm厚的铝氧化物为势垒膜,直接制备出了室温隧穿磁电阻(TMR)为30%—48%的磁性隧道结,其结构为Ta(5nm)/Cu(25nm)/Ni79Fe21(5nm)/Ir22Mn78(10nm)/Co75Fe25(4nm)/Al(0·8nm)-O/Co75Fe25(4nm)/Ni79Fe21(20nm)/Ta(5nm).同时,利用刻槽打孔法和去胶掀离法两种光刻技术并结合Ar离子束刻蚀及化学反应刻蚀,制备出面积在4μm×8μm—20μm×40μm、具有室温高TMR和低电阻的高质量磁性隧道结.300℃退火前后其室温TMR可分别达到22%和50%.研究结果表明,采用光刻中的刻槽打孔或去胶掀离工艺方法制备的小尺寸磁性隧道结,可用于研制磁动态随机存储器和磁读出头及其他传感器件的磁敏单元.更多还原

【Abstract】 In this work, on the one hand, the contact-shadow-mask method and technique were used to micro-fabricate the magnetic tunnel junction （MTJ） and optimize the experimental conditions. The width of the gap for the long and narrow top or bottom magneto-electrode is 100 μm, which can be used to deposit MTJs and form a cross strip with the tunnel section of 100 μm×100 μm. The MTJs with tunneling magnetoresistance （TMR） ratio of 30%—48% can be directly obtained for the structure of Ta（5 nm）/Cu（25 nm）/Ni 79Fe 21（5 nm）/Ir 22Mn 78（10 nm）/Co 75Fe 25（4 nm）/Al（0.8 nm）-O/Co 75Fe 25（4 nm）/Ni 79Fe 21（20 nm）/Ta（5 nm）. On the other hand, the MTJs with high TMR ratio and small active area from 20 μm×40 μm down to 4 μm×8 μm were fabricated using two optical lithography methods of milling contact hole and lift-off resist, combined with Ar ion-beam etching or CF₄ reactive etching techniques. Then, the TMR ratio from 22% up to 50% can be achieved before and after annealing at around 300 ℃ for 1 h. Our investigation shows that the patterned MTJs, which were microfabricated using the two optical lithography methods stated above, can be used as the fundamental element of magnetoresistive random access memory, magnetic read-heads in hard disk drives and the field sensitive sensor.更多还原