In these sensor, although SQUID can explore intensity of dinky magnetic induction (FT) , but plant need low temperature is cooling, and suffer electromagnetism interference easily, for the magnetic flux of peripheral equipment; with this complex need door magnetometer has volume big, power comsumption Xiaohe of big, moving limits cannot detect the character of static magnetic field, restricted its to apply sensor of effect of; Huo Er to show increase sensitivity to need to rely on to increase power comsumption realizes; and AMR sensor asks deposit is magnetic material and automatic and corrective system, and appear when a few MT easily saturated; because MEMS technology is OK will traditional magnetism sensor miniaturization, because this is based on the magnetism sensor of MEMS to have volume small, function tall, cost low, Gao Lingmin and batch produce low, power comsumption wait for an advantage, its preparation material is given priority to with Si, disappear must use special and magnetic material to reach its to be opposite besides magnetism sensor preparation the influence of the magnetic field that be measured. The article is to be based on the magnetism sensor of MEMS at present in preparation process involved main design, make, pass feeling technology and property of parts of an apparatus to undertake summing up, undertake expectation to its future development.

 

1, design of MEMS magnetism sensor and make

 

1.1MEMS magnetism sensor is designed

 

To obtain high-powered MEMS magnetism sensor, want to undertake designing to parts of an apparatus according to the applied object of parts of an apparatus above all, the working principle of the structure that determines parts of an apparatus from this, use data, application and inductive technology. MEMS design personnel is OK the optimal technology that makes sensor according to imitate and choice of the tool that build a model and material, forecast the performance of MEMS magnetism sensor. At the same time design personnel must consider parts of an apparatus to make a process answer the material of comply with grows, parts of an apparatus is made, the regulation such as the implementation of signal modulation and inductive technology, produce the mistake that affects sensor performance in order to avoid. When development business uses MEMS sensor, must consider the following: Optimize structure of parts of an apparatus to design; to pack a design; Reliable material function and metric system make technology; Design and emulate a tool suitably; Reduce electronic noise and parasitism electric capacity; Reliable signal processing system; Reliable test.

 

The MEMS that often uses at present designs MEMSCAP of kit draw together, CoventorWare, IntelliSuite and Sandia Ultra-planar Multi-level MEMS Technology (SUMMiTV) . These design tools have the module that establishs sensor domain and examination design regulation, and can the measure of process of imitate small treatment, be helpful for reducing the time that wins sensor of high-powered MEMS magnetism.

 

1.2MEMS magnetism sensor is made

 

Normally, the production of sensor of MEMS magnetic field can use system or craft of exterior small treatment comes true. Because silicon is had,very good machinery is used to with electricity property basically process data as its, for example, silicon has the smallest mechanical lag and the fracture stress that are close to 1GPa. In addition, silicon is after impure phosphor or boron its report function is attainable clear improvement.

 

Craft of body small treatment is to use wet etch with dry method technology, the isotropy that passes data and anisotropy etch the material composition that preparation place needs. Craft of exterior small treatment is the deposit that has different material layer through be on underlay, design is changed and etch the production that realizes pair of MEMS parts of an apparatus. Normally, these layers are used as structure and sacrificial layer. Graph the SEM of the 1 magnetism sensor that gave out to pass preparation of craft of small treatment of body treatment and surface respectively.

 

Graph the SEM that 1 body treatment and exterior treatment obtain

 

2, pass feeling technology and MEMS magnetism sensor

 

2.1 pass feeling technology

 

Can use pass sensor of magnetism of MEMS of feeling technology preparation differently, press block type, capacitance and optical technology for example. These technologies can change magnetic field signal into telegraphic date or smooth signal respectively. Detect in telegraphic date in, suffer when power source when be restricted or be being put in strong electromagnetism to disturb, can affect its to apply. And smooth signal detects transmit in action of strong electromagnetism field and Sunday run wait for the application below the condition to detect than telegraphic date have an advantage more, because this often applies in extreme circumstance. In addition, to obtain high resolution and sensitivity, the signature that MEMS magnetism sensor needs to deserve to have low electron noise and parasitism electric capacity makes a system.

 

Sensor of magnetism of 2.2 of all kinds MEMS

 

V. The magnetometer of MEMS of Lorentz force resonance that the report such as Kumar realizes through amplifier of oscillation of block of in-house hot pressing has extremely tall sensitivity. They are used slant method of tuning of buy electric current, the active character factor resonator from 680 raise 1.14×10^6, already proved interior magnifies coefficient raised 1620 times. In addition, resonator slants the addition of buy electric current besides the quality factor that improves parts of an apparatus, also make the sensitivity of parts of an apparatus rose 2400 times (arrive from 0.9 μV·nT^(-1) 2.107 MV·nT^(-1)) . Slant in dc when buy electric current is 7.245 MA, obtain the greatest sensitivity to be 2.107 MV·nT^(-1) , background noise is 2.8 PT·Hz^(-1/2) .

 

E. The report such as Mehdizadeh be based on Luoluncili to lead the MEMS magnetism sensor that makes on N SOI underlay in low resistance, if the graph is shown 2 times,the SEM of its major component and electrical continuity bonding part. This sensor used pair of board silicon resonator (ply 10 μm, among them one of golden line) that have 10 μm X 200 Nm, 2 when design among its narrow bridge and; of join of 2 Si board are in when resonator below planar and oscillatory mode when oscillation, it can be mixed by periodic drawing reduce stress, because this appears,press block character. The quality factor of humorous resonator is magnified below atmosphere (from 1140 to 16900) . In addition, this sensor can heighten its sensitivity through increasing resonator vibration scope. In air, it is when syntonic frequency 2. Factor of 6 MHz, quality is 16900 when, obtain sensor sensitivity to be 262 MV/T.

 

Graph the SEM of major component of sensor of magnetism of MEMS of the 2 type that control block and electrical continuity bonding

 

A. L. The preparation such as Herrera-May the MEMS magnetism sensor that has simple resonator and linear report to answer. It by perforation board (472μm X 300 μm X 15 μm) , curve bridge 4 times (2 18 μm X 15 μm X 15 μm) , bridge that prop up (60 μm X 36 μm X 15 μm) and 4 P pressure quick bridge forms the Hui Sideng that resistor forms, see a picture 3. In the system that the level uses on SOI underlay small treatment craft makes parts of an apparatus or appliance, the dynamic limits that controls parts of an apparatus through adjusting incentive electric current makes its maintain linear report to answer, obtain factor of quality of parts of an apparatus for 419. 6, sensitivity is for 230 MV·T, resolution 2. 5 μT, power comsumption is 12 MW. The magnetic test that this sensor suits to apply at nondestructive and blemish of iron magnetism material detect with what corrode.

 

The top view of body of magnetism sensor of graph 3 MEMS is pressed with 4 quick the Hui Sideng bridge that resistor constitutes

 

The preparation such as Langfelder the sensor of MEMS magnetic field that has capacitance to numerate, this sensor can detect as perpendicular as syntonic structure surface direction (Z axis) magnetic field. It secures stator and the clip composition with two fine pensile bridge by a group, form 2 poor cent to make the same score C1 of container of andante quick electrification and C2, see a picture 4. Have the bridge of sensor resonance frequency, connecting when having electricity with magnetic field interaction, make 2 fine bridge are used Luo Lunci by master piece thereby. This force is perpendicular the plane that makes at magnetic field and alternating current place, bring about bridge and displacement of smooth andante generation, this displacement can divide the change of capacitance to detect through difference. Sensor is 150 μV·μT^(-1) , academic noise in the total sensitivity when electric current of peak value drive is 250 μA for 557. 2 μV·Hz^(-1/2) , resolution is made an appointment with for factor of 520 NT·mA^(-1)·Hz^(-1/2) , quality 328, resonance frequency is 28.3 KHz.

 

Graph the sketch map of the sensor of MEMS magnetic field that the 4 clip that prop up by smooth andante, fixed stator and 2 fine bridge form

 

M. The design such as Li by curve bridge resonator (the magnetic field sensor that 1200 μm X 680 μm X 40 μm) comprises. Curve bridge resonator and the Si Liang Tong that carry electricity to cross coupling of small lever mechanism, 30 fork of every a side that resonator have the aid of curves bridge show electrode realizes electrostatic drive and capacitance induction, the sensitivity that obtains sensor is for factor of 6687 Ppm·mA^(-1)·T^(-1) , quality 540, syntonic frequency is 21.9 KHz (1 Ppm = 10^(-6)) .

 

Aditi through using SOI and glass piece preparation of zincous bond technology sensor of MEMS magnetic field. This parts of an apparatus makes craft have the following advantage: Microtherm (≤400 ℃ ) , reliable, can repeat, little photoetching measure and the capacity that can control the distance between electrode. Obtain sensor power comsumption to be 0.45 MW, resolution is 215 NT·Hz^(-1/2) .

 

B. The design such as Park mix by silicon resonator compact model the magnetic field sensor that laser locates the system is formed, if pursue,5 are shown. This system has photoelectricity detector and laser diode, use at monitoring electric current to slant the illuminator angular displacement of buy. Resonator has aluminous layer by besmear Fu (the silicon film of 2500 μm X 2500 μm X 0.8 μm) (composition of 3000 μm X 3000 μm X 12 μm) , film turns round bedspring by two (2100 μm X 100 μm X 12 μm) is propped up, width is for 30 μm, ply 0. The aluminum steel deposit of 8 μm is on its. The displacement of the magnetic field that bring to bear on and retrorse lens is concerned, slant when coil when buy electric current is 50 MA, the sensitivity that obtains sensor is factor of 364 Hz, quality for frequency of 62 MV·μT^(-1) , resonance 116, the resolution of 53 MHz bandwidth is 1.78 NT·Hz^(-1/2) for noise of 0.4 NT, background.

 

Graph the sensor of MEMS magnetic field that 5 bright numerate and graph of sensor job principle

 

M. Lara-Castro put forward to be in printed circuit board on the system of portable signal modulation of the sensor of MEMS magnetic field of implementation, it deserves to have can the 2 sine signal generator of sensor of humorous magnetic field. Magnetic field sensor by resonance silicon structure (a 600 μm X 700 μm X 5 μm) , aluminous annulus (1 μm is thick) with 4 P model pressure quick bridge forms the Hui Sideng that resistor comprises. The frequency stability of 2 signal generators is ±100 Ppm, resolution is 1 Hz. In this system, magnetic field and voltage have the sensitivity below atmosphere of; of similar line sexual relationship and resolution to be 0.32 V/T and 35 NT respectively.

 

Long Liang use MEMS magnetism to twist place and detect the capacitance that need branch made MEMS magnetism sensor. Magnetism is twisted placing is the silicon through bridge is being decided in Shuang Duangu film of CoNiMnP permanent magnetism is made obtain on film, magnetism sensor dimension is 3.7 Mm X 2.7 Mm X 0.5 Mm, the MEMS magnetism sensor of preparation has good linear, sensitivity is 27.7 FF/mT, the smallest distinguishable magnetic field size is 36 NT.

 

3, look into

 

The sensor of magnetism of MEMS syntonic type that is based on Lorentz force at present is main will detect through pressing block, optics and capacitance feeling to measure a technology magnetic field. These technologies can provide the optimal sensor means that develops specific application circumstance to design staff, for example, the feeling that control block is measured comfortable at using system small treatment craft comes true and simple signal processing system. But deflection of voltage of existence of the induction that control block, and resistor suffers temperature effect easily, because the need in this system offers temperature,compensate circuit. Capacitance feeling is measured basically come true through craft of exterior small treatment, the magnetic field changeover that brings to bear on place outputs signal for report. This technology has very small temperature dependence, allow electronic circuit and magnetism sensor to make go up in same chip. Normally, the sensor of capacitance induction has tall air damp below atmosphere, need to undertake to parts of an apparatus vacuum encloses ability to heighten its sensitivity to avoid its effect. Because the sensor that uses preparation of optical and sensitive technology has the character that fights electromagnetism interference, because the place in this system needs circuit to be mixed than capacitance,control block of sensitive technology little, can work in harsh environment, craft of small treatment of the surface and body all applies to this kind of good point that passes feeling technology. However, these feeling measure a technology to existing to cause the problem with sensor calorific structure as a result of joule effect, this meeting produces the displacement of thermal stress and resonator. For this, need comes loose to parts of an apparatus further machinery of hot, resonator can accuse gender and vacuum to enclose research, acquire property of better MEMS magnetism sensor in order to ensure.

 

Make technical maturity as the development of technology of small accept rice, small machine, more and more sensor begin to side with compositive change, intelligence is changed and network way develops, they already became industry to produce the main power that implementation intelligence produces. Its intelligence application basically is in as follows a few respects:

 

(1) passes feeling technology. Compose builds sensor network system, assure to undertake to information collect, conformity and transmit, make industry produces a process to gain more effective control.

 

(2) numerical control is produced. Total masterstroke mode is passed online diagnose, implementation is controlled to the appearance of integral industry product line.

 

(3) automatic production and machinery. Use automation technology to begin mechanical production, can improve manufacturing efficiency and quality significantly.

 

4, last word

 

The article was summed up be machined through body and the exterior treatment method, MEMS magnetism sensor that uses those who press block, capacitance and optical technology preparation to be based on Luoluncili, introduced factor of the sensitivity of all sorts of structural magnetism sensor, quality, noise and the character such as exploration limit. As accept rice technology, compositive change technology and the ceaseless development that enclose a technology, the high-powered, intelligence sensor that can monitor many physical quantity at the same time meets more appear ceaselessly.