高磁电阻磁性隧道结的几种微制备方法研究  

Microfabrication methods of magnetic tunnel junctions with high tunneling magnetoresistance

作　　者：李飞飞[1] 张谢群[1] 杜关祥[1] 王天兴[1] 曾中明[1] 魏红祥[1] 韩秀峰[1] 

机构地区：[1]中国科学院物理研究所磁学国家重点实验室,北京100080

出　　处：《物理学报》2005年第8期3831-3838,共8页Acta Physica Sinica

基　　金：国家重点基础研究发展规划(批准号:2001CB610601);国家杰出青年科学基金(批准号:50325104);国家自然科学基金(批准号:10274103)资助的课题.~~

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.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 mu m, which can be used to deposit MTJs and form a cross strip with the tunnel section of 100 mu m x 100 mu m. The MTJs with tunneling magnetoresistance (TMR) ratio of 30%-48% can be directly obtained for the structure of Ta(5 nm)/Cu(25 nm)/Ni79Fe21(5 nm)/Ir22Mn78(10 nm)/Co75Fe25(4 nm)/Al(0.8 nm)-O/Co75Fe25(4 nm)/Ni79Fe21(20 nm)/Ta(5 nm). On the other hand, the MTJs with high TMR ratio and small active area from 20 mu m X 40 mu m down to 4 mu m x 8 mu m 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 he achieved before and after annealing at around 300 degrees C 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.

关 键 词：磁性隧道结 制备方法 动态随机存储器 隧穿磁电阻 离子束刻蚀 工艺条件 铝氧化物 铁磁电极 狭缝宽度 直接制备 化学反应 光刻技术 M-20 研究结果 工艺方法 传感器件 TMR 掩模法 室温 低电阻 小尺寸 金属 打孔 刻槽 势垒 

分 类 号：TB39[一般工业技术—材料科学与工程]