Study On High Performance Driving Structure For Giant Magnetoresistance Sensors

1/f noise is the major noise of giant magnetoresistive(GMR) sensors, which limits detection ability at low frequency. Supported by National Nature Science Fund, our team has proposed vertical motion flux modulation structures which can suppress 1/f noise and improve the detection ability. And modulation structure is a key factor which plays an important role on power consumption, anti-jaming ability as well as modulation efficiency. So it is significant to study high performance modulation structure.In this paper, micro bridge and cantilever has been studied and compared, advantages and disadvantages have been analysised in anti-jaming, quatility factor and power consumption when applied to vertical flux modulation. My works are as follow.Vertical flux modulation is described and the importance of modulation structure is explained. Also influential factors of resonance frequency and amplitude of both micro bridge and cantilever are analysed and compared. Then equivalent circuit model of piezo electric vibrator generator is given and the access to equivalent parameter is expressed.Libration performance of different modulation structures are analised by finite element model. The modes of micro bridge and cantilever are anslysied in finite element model to find the most suitable mode for vertical modulation. Then anti-jaming ability is simulated showing that micro bridge is better than that of cantilever.Two kinds of modulation structure are designed and fabricated, including the designing of structure size, the process of making modulation film and silicon structure, consiting of making electric film, photoetching and silicon etch.Quality factor and frequency stability of different structures are measured and compared, showing that quality factor and frequdncy stability of bridge are better than that of cantilever, indicating that micro bridge has advantages over cantilever in magnetic flux modulation.