| Recently, the anisotropic magnetoresistive (AMR) sensor is one of the most important magnetic field sensors in the field. The AMR sensor, in which Barber-Pole and AMR thin film are integrated, is fabricated through microelectronic, micromachining and thin film technologies. It is a device of new generation that has the advantages of small size, high sensitivity, low power consumption, ease of integration and batch production. In this thesis, the process of AMR thin film and sensor preparation is studied, the test system is established, the output properties are measured and the structure and performance of the AMR sensor is optimized.To obtain inducing magnetic field in the sputtering equipment, a special substrateholder has been designed and the AMR film whose ΔR_m/R reaches 2.8% has beenobtained. By researching on the preparation process, the dependence of ΔR_m/R onthe substrate temperature and sputtering power was found and thereby the process parameters were optimized.ANSYS is used to develop an electric field model to analyze the Barber-Pole with different direction in an AMR sensor. Then the curves of the resistance's relative rate of change versus normalized magnetic field are given, which shows that when the width of AMR resistor strip is double of the distance between the Barber-Pole, the output of 50° Barber-Pole sensor is of good symmetry. The result provides the theoretic basis to improve the symmetry of the output curve of the sensor with Barber-Poles and optimize the performance of the AMR sensor.With a lot of experiments, the problems encountered in the process, e.g., the etching of AMR resistor strip, the photoetching of Barber-Pole and the surface clean in... |
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