Title :
Spin dependent tunnel junctions for memory and read-head applications
Author :
Freitas, Paulo P. ; Cardoso, Susana ; Sousa, Ricardo ; Ku, Wanjun ; Ferreira, Ricardo ; Chu, Virginia ; Conde, João P.
Author_Institution :
INESC, Lisbon, Portugal
fDate :
9/1/2000 12:00:00 AM
Abstract :
Spin dependent tunnel junctions with TMR exceeding 30-40% can now be prepared with AlOx and AlN barriers, with junction resistance tuned from 30-40 Ω×μm2 to 108 Ω×μm2. Thermal stability is better than 3000% for thicker barriers (>11 Å) but is degraded to 220°C for 6 Å barriers. A 9 bit MRAM cell is demonstrated using tunnel junctions and vertically integrated a:Si diodes. Junction switching is achieved with on chip 20 ns field pulses. Requirements for tunnel junctions for 100 Gb/in2 read head applications are discussed. First prototypes of tunnel junction read heads with 600 Å read gaps were fabricated, where the TJ is at the air bearing surface. TMR loss was observed during the final head lapping steps
Keywords :
magnetic film stores; magnetic heads; magnetoresistive devices; random-access storage; thermal stability; tunnelling; 20 ns; 600 angstrom; 9 bit; AlN; AlO; MRAM cell; Si; TMR; air bearing surface; field pulses; head lapping steps; junction resistance; junction switching; read-head applications; spin dependent tunnel junctions; thermal stability; tunnel magnetoresistance; Contacts; Diodes; Lapping; Magnetic heads; Oxidation; Plasmas; Prototypes; Thermal degradation; Thermal stability; Tunneling magnetoresistance;
Journal_Title :
Magnetics, IEEE Transactions on
