Spin dependent tunneling junctions have been fabricated by rf sputtering and photolithography patterning. The junctions have adequate thermal stability to withstand the high temperatures encountered in backend microelectronics integration processing with on-chip IC (from 275 to 300/spl deg/C for one hour) and standard component packaging (200/spl deg/C for six hours). These materials also have the potential for long term device operation at high temperatures of at least 150/spl deg/C-there is little change in the properties upon additional annealing at 150/spl deg/C for 510 hours, after being pre-annealed at 275/spl deg/C for two hours. With excellent intrinsic physical properties such as a high JMR ratio of <20%, a low coercivity of >10 Oe, a high resistance, a wide bandwidth, and room temperature operation, SDT materials are superior to other technologies for low field, low power, and low cost applications. With the ability of microelectronics fabrication processing and the compatibility of backend integrating process with IC on-chip, this new technology holds great potential for commercialization in magnetic field sensing devices.
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