Reserch On The Spin Valve Sensor Based On GMR Effect

Today, RF inductor device is a passive component that can be used in high-frequency circuits, which become the main focus among researchers. Its inductance value, quality factor, self-resonance frequency have been important parameters affecting the performance of RF circuits and equipment in recent years. Since the board-level RF circuit becomes larger and larger, taking up more space, SOC has become the development trend and fashion. So how can it be compatible with CMOS technology, adapting miniaturization, integration trend is a difficult problem that should be overcome. This paper is a study for the above problems. It designs and simulates a kind of spiral inductor used in RF circuits that can be well compatible with CMOS technology.Firstly, we elaborate the domestic and foreign research background RF inductor, pointing out the main factors that now limit RF inductors development at home and abroad. This paper discusses the main problem of the current RF inductor from the choice of materials, structural design, process preparation and the overall inductance device fabrication and important way to improve the device parameters. It lays a good theoretical basis for the subsequent preparation of inductive devices.Subsequently, in order to obtain a better performance RF inductor, in terms of magnetic materials, FeCo-TiO2 particles of a high-frequency soft magnetic films were prepared by way of magnetron sputtering, the film having a good high frequency performance can be a high-frequency inductor core material. From the device fabrication aspects, the analysis produced a series of problems that may be encountered from the RF inductor main difficulty process, which mainly include photolithographic lift-off process, polyimide and electroplating copper process technology. Especially, we focus on PI etching, pathway,curing problems and the copper plating process. The detailed discussion of the general operational process offers many valuable lessons.Again, we use electromagnetic simulation software HFSS modeling and simulation the air coin inductors, analyzing the important structural parameters that affect the performance.The optimized results show that the air coil inductor having line width of 15μm, line spacing of 10μm, coil thickness of 5μm is better performed.It is discussed in detail in the production process of air coin spiral inductors and we get 4.5 turn air coin conductor by MEMS process.The test results indicate that the inductance is about 55 nH/mm2 when the frequency is below 1Ghz and the quality factor reaches its maximum in the 1.2GHz, about 8, slightly lower than the simulation results.Finally, we design the RF inductor on the basis of the air core inductor and analysis the structure parameters affecting the performance.The optimized results show that the inductor having line width of 15μm, line spacing of 10μm, coil thickness of 5μm is better performed. The test results indicate that the inductance is about 83 nH/mm2 when the frequency is below 1Ghz and the quality factor reaches its maximum in the 1GHz, about 6.The inductance has a increase of 50.6% while the quality factor has a decease of 25%.It is discussed in detail in the production process of RF spiral inductors and analyzed the problems when adding the magnetic film.By compared with the simulation result, which provides a large experimental basis for follow-up work.