CN101718801B - Micro-accelerometer based on high electron mobility transistor (HEMT) - Google Patents

Abstract

The invention relates to the field of micro-accelerometers, in particular to a micro-accelerometer based on a high electron mobility transistor (HEMT), which adapts to the requirement on the micro-accelerometer application field for high-sensitivity micro-accelerometers and realizes the application of a force-electricity conversion mechanism of the high electron mobility transistor (HEMT) to the micro-accelerometer. The micro-accelerometer is manufactured by the following steps of: 1, growing a film with a material layer structure shown in the list 1 on a GaAs substrate by applying a molecular beam epitaxy technology; 2, processing the high electron mobility transistor (HEMT) on the film by applying a micro-electromechanical element processing technology; and 3, processing a micro-accelerometer by applying the micro-electromechanical element processing technology. The invention effectively utilizes the force-electricity conversion mechanism of the high electron mobility transistor (HEMT), realizes the application of the high electron mobility transistor (HEMT) to the micro-accelerometer, has high sensitivity and good linearity, and can completely adapt to the actual requirement of the micro-accelerometer application field.

Description

Micro-acceleration gauge based on high electron mobility transistor (HEMT)

Technical field

The present invention relates to the micro-acceleration gauge field, specifically is a kind of micro-acceleration gauge based on high electron mobility transistor (HEMT).

Background technology

Existing micro-acceleration gauge mostly is the silicon piezoresistance type accelerometer, piezoresistive effect based on silicon piezoresistive pressure sensor is realized, utilize silicon piezoresistive pressure sensor to realize detecting with the linear response of external pressure,, technical maturity simple in structure because of it, working band are wide etc., and plurality of advantages becomes one of the research focus in little inertia device field.But because the restriction of silicon piezoresistive pressure sensor piezoresistance coefficient is difficult to further improve response sensitivity; In addition, the change in resistance of silicon piezoresistive pressure sensor is subjected to Temperature Influence bigger, diminishes rapidly with the rising of temperature, and above-mentioned shortcoming has all limited the application of silicon piezoresistive pressure sensor on high sensor.

Therefore, for adapting to micro-acceleration gauge application pressing for to the high sensitivity micro-acceleration gauge, in recent years, the various countries scientist begins field effect transistor is applied to the research of micromechanics sensing arrangement in succession, and in the middle of research, prove the feasibility that field effect transistor is applied to micro-acceleration gauge, verified the highly sensitive characteristic that micro-acceleration gauge possessed of applied field effect transistor.Show according to relevant report both domestic and external, present various countries scientist's research direction metal-semiconductor field effect transistor (the Metal-Semiconductor Field-Effect Transistor in field effect transistor that focuses mostly on, MESFET), metal-oxide layer-semiconductor-field-effect transistor (Metal-Oxide-Semiconductor Field-Effect Transistor, MOSFET).Yet there are no High Electron Mobility Transistor is applied in correlative study on the micro-acceleration gauge.

Described High Electron Mobility Transistor (High Electronic Mobility Transistor, be called for short HEMT) is to grow up early 1980s, is based on modulation doping and a kind of novel transistor of setting up.High electron mobility transistor (HEMT) adopts modulation-doped structure, undope in heterojunction narrow bandgap semiconductor material one side, and at wide bandgap semiconductor materials one side doping donor impurity, donor impurity ionization produces electronics and positively charged alms giver's ionized impurity center like this.The Fermi level of the wide bandgap semiconductor materials that the n type mixes in high electron mobility transistor (HEMT) is near conduction band, and the Fermi level of narrow bandgap semiconductor material is substantially in the centre position in forbidden band, because the fermi level position difference of heterojunction two layers of material, electronics will be transferred to lower low bandgap material one side from higher relatively wide bandgap material one side of Fermi level, make electronics and alms giver's ionized impurity apart in the raceway groove, in raceway groove, form two-dimensional electron gas (2DEG).Simultaneously, set up a highfield by space charge, under the effect of highfield, near can the be with heterojunction boundary bends.Under the extra electric field effect, band curvature strengthens, and so just can form narrow inversion layer potential well, forms quantum well in raceway groove.Because the de Broglie wave wavelength of the width of quantum well and electronics is comparable, energy generation quantization on perpendicular to the z direction of heterojunction boundary, 2DEG loses degree of freedom in the motion of z direction, only in that be parallel to can free movement on the X at interface, the Y direction.2DEG has many noticeable characteristics, and its electron mobility μ is far above the electron mobility of body material.By the non-doping separation layer of growth between doped layer and raceway groove, make the further apart of 2DEG and alms giver's ionized impurity center, reduced the influence of ionized impurity scattering, further improved mobility.Under the low temperature, the influence of ionized impurity scattering reduces, and the electrons transport property of 2DEG is more superior.

Compare with common field effect transistor, the raceway groove transmission of HEMT has utilized quantum size effect.Owing on the one dimension direction, utilize the band-edge energy difference of heterojunction that electronics is limited, make the quantization of energy of electronics in lengthwise movement, formed the very two-dimensional electron gas of high concentration (2DEG).2DEG motion in a lateral direction is unrestricted in the raceway groove, and is separated from each other on channel electrons and the donor ion space, thereby channel electrons is subjected to the foreign ion scattering process hardly when lateral transport, thereby has very high mobility.And the strong concentration that depends on 2DEG in the raceway groove of the channel conduction of HEMT, when the channel part material is subjected to stress, the band structure generation respective change of semiconductor material, can cause restriction to change, have influence on the concentration of raceway groove 2DEG, as utilize this nano effect to come the conversion of realizable force electricity, can greatly improve the detection sensitivity of microsensor.

Summary of the invention

The present invention is in order to adapt to the needs of micro-acceleration gauge application to the high sensitivity micro-acceleration gauge, realize the application of high electron mobility transistor (HEMT) power electricity switching mechanism on micro-acceleration gauge, a kind of micro-acceleration gauge based on high electron mobility transistor (HEMT) is provided.

The present invention adopts following technical scheme to realize: based on the micro-acceleration gauge of high electron mobility transistor (HEMT), adopt the following steps processing and manufacturing:

1, use molecular beam epitaxy technique grows material layer structures as shown in table 1 below on the GaAs substrate film:

Table 1

2, use the micro electro mechanical device process technology and process high electron mobility transistor (HEMT) as follows:

A, according to the layout of micro-acceleration gauge structure to be processed, remove all films except that the film of required processing high electron mobility transistor (HEMT) position on the GaAs substrate with etching technics; For example: the micro-acceleration gauge of processing four limits, four girder constructions, then need to keep four films that are used to process high electron mobility transistor (HEMT), and the film retention position is being " ten " word distribution (being that the film retention position is distributed on four ends of " a ten " font) on the GaAs substrate; And the work sheet cantilever beam structure then only keeps monolithic films to get final product on the GaAs substrate;

B, on the GaAs substrate, respectively keep the film place and process high electron mobility transistor (HEMT) respectively:

B1, at first adopt photoetching process to process the source electrode of high electron mobility transistor (HEMT) and the Ohmic contact figure of drain electrode, adopt electron beam evaporation process to form then on ohmic contact layer n-GaAs surface on the ohmic contact layer n-GaAs surface of described film

Thick Au/Ge/Ni overlayer, after after peeling off cleaning, with 400 ℃ of high temperature quick alloy in 60s, realize source electrode, the drain metallization of transistor HEMT, make between the ohmic contact layer n-GaAs surface of source electrode, drain electrode and described film of transistor HEMT and form good Ohmic contact, wherein, the source electrode of high electron mobility transistor (HEMT) is provided with for separating, promptly constitute, and the orientation of two separated source is parallel with drain electrode by two separated source;

B2, on the film between source electrode and the drain electrode, process and drain parallel and run through the groove of whole film, and groove is a groove bottom with the schottky contact layer n-AlGaAs surface of film with etching technics; In the middle of the groove bottom land, process the grid groove with photoetching process then along groove direction, and in grid groove process, detection resources is leaked the saturation current of two interpolars in real time, the saturation current that leaks two interpolars until the source reaches required value, obtain required grid groove, adopt electron beam evaporation process in groove surfaces, grid groove, to form subsequently

Thick Ti/Pt/Au overlayer forms grid to peel off method at grid groove place, realize the gate metalized of transistor HEMT, the good Schottky barrier of formation between the grid that makes transistor HEMT and the schottky contact layer n-AlGaAs of described film;

B3, with the PECVD sedimentation on the film that processes high electron mobility transistor (HEMT) source electrode, drain electrode, grid with 230 ℃ of temperature deposits

Thick Si ₃N ₄Passivation layer is then with the described Si of photoetching process etching ₃N ₄Passivation layer makes Si ₃N ₄The passivation layer zone only cover between source electrode and the drain electrode and source electrode and drain electrode over against the edge of side;

1., covering Si b4, processing connects the air bridges of two separated source between two separated source: ₃N ₄Apply photoresist on the film of passivation layer, and to use that photoetching process forms directly over two separated source be two bridge pier shape grooves of groove bottom with two separated source upper surfaces respectively, adopts electron beam evaporation process or sputtering technology to cover in the surperficial and bridge pier shape groove at photoresist then

Thick TiAu or TiW double base metal level; 2., at TiAu or TiW double base layer on surface of metal coating photoresist, using photoetching process once more forms with TiAu or TiW double base metal level directly over two separated source to be the bridge connected in star of groove bottom, to adopt electroplating technology to electroplate the thick Au layer of 2～5 μ m then on TiAu or TiW double base metal level; 3., with the photoresist above organic solvent dissolution TiAu or the TiW double base metal level, erode Au layer below TiAu or outer all TiAu or the TiW double base metal level of TiW double base metal level then, use photoresist remaining on the described film of organic solvent dissolution at last, promptly obtain described air bridges, finish the high electron mobility transistor (HEMT) processing on the described film;

3, use the micro electro mechanical device process technology and process the micro-acceleration gauge structure as follows:

Use etching technics the GaAs substrate etching is become by peripheral pedestal, semi-girder and by semi-girder to prop up the micro-acceleration gauge structure that the mass that is suspended from peripheral pedestal central authorities constitutes, and make the described film that is processed with high electron mobility transistor (HEMT) be positioned at the junction of semi-girder and peripheral pedestal.

In addition, the processing of described micro-acceleration gauge also comprises respectively and high electron mobility transistor (HEMT) source electrode, drain electrode, the processing of drawing pad that grid is corresponding, and corresponding to draw specifically being processed as of pad conventionally known to one of skill in the art, therefore is not described in procedure of processing of the present invention.

When micro-acceleration gauge of the present invention is experienced acceleration movement, mass produces skew, drive semi-girder and produce distortion such as distortion or bending, can make in the high electron mobility transistor (HEMT) raceway groove of semi-girder root setting and produce STRESS VARIATION, respective change will take place in the band structure of semiconductor material, cause two-dimensional electron gas 2DEG restriction to change, have influence on the concentration of 2DEG in the raceway groove, finally be reflected to the I-V characteristic variations (as shown in Figure 7) of HEMT, utilize suitable peripheral circuit that but this variation is converted to measuring-signal, as voltage, the output of forms such as electric current, just can set up output signal and by the relation between the measuring acceleration through demarcating, thereby to measure extraneous acceleration.Etching technics in molecular beam epitaxy technique of the present invention, the micro electro mechanical device process technology, photoetching process, PECVD sedimentation etc. all are known, ripe processing technologys.

High electron mobility transistor (HEMT) at micro-acceleration gauge of the present invention and upward setting thereof has carried out a series of test experiments as follows respectively:

1, the high electron mobility transistor (HEMT) that is provided with on the micro-acceleration gauge is carried out the semiconductor parametric test experiment: utilize the electrology characteristic of semiconductor parameter specificity analysis instrument Agilent 4156C analysis high electron mobility transistor (HEMT), V _GSBe-2.3～0.7V, step-length is 0.5V, and the output characteristic curve of high electron mobility transistor (HEMT) and transfer characteristic curve are respectively as shown in Figure 3 and Figure 4.Test result shows that the high electron mobility transistor (HEMT) that is provided with on the micro-acceleration gauge is functional, and its threshold voltage is about-2.8V, meets design requirement;

2, micro-acceleration gauge is carried out the static pressure experiment, verify micro-acceleration gauge under the condition of static state pressurization, the I-V characteristic of micro-acceleration gauge and the situation of change of transfer characteristics.Output characteristic curve before and after the pressurization and transfer characteristic curve are respectively as shown in Figure 7 and Figure 8.

As can be seen from Figure 7, pressurization back I-V family curve has taken place to move, and changing comparatively tangible zone is the saturation region, and moves obvious more on the big more curve of grid voltage; As can be seen from Figure 8, pressurization back transfer characteristic curve slope becomes big, and plots changes is consistent with I-V family curve variation tendency.

3, micro-acceleration gauge is carried out piezoresistance coefficient gravity experiment: the I-V family curve comparison diagram of using Agilent 4156C characteristic of semiconductor analyser test micro-acceleration gauge high electron mobility transistor (HEMT) when being parallel to the high electron mobility transistor (HEMT) direction of growth (Z direction) acceleration for ± 1g, wherein, gate source voltage is from-2.3～0.7V, step-length is 0.6V, show as shown in Figure 5, ± electric current of high electron mobility transistor (HEMT) changes during 1g; Use Polytec micro-system analyser and measure micro-acceleration gauge micro-cantilever of the present invention-mass block structure full-size(d), bring data into ANSYS software and carry out the stress simulation analysis that the Z directional acceleration is 1g, estimate the semi-girder maximum stress, according to the piezoresistance coefficient formula $\mathrm{\π}=\frac{\mathrm{\ΔI}}{\mathrm{I\σ}}=(1.72\±0.33)\×{10}^{-7}{\mathrm{Pa}}^{-1},$ Wherein, σ is a stress, and I is a current value, and Δ I is the changing value of electric current.

Checking by analysis in addition, the graph of a relation of drafting high electron mobility transistor (HEMT) drain voltage and piezoresistance coefficient as shown in Figure 6, show piezoresistance coefficient difference under the different bias voltages of high electron mobility transistor (HEMT), the variation of saturation region is more obvious than linear zone, and the maximum piezoresistance coefficient of GaAs material HEMT exceeds three orders of magnitude than SI (silicon) material voltage dependent resistor (VDR), illustrate high electron mobility transistor (HEMT) be a significant benefit to highly sensitive and that resistance is adjustable is little/receive and use on the dynamo-electric piezoresistive device.

In addition, micro-acceleration gauge of the present invention is inserted peripheral circuit, carry out the static state pressurization and trigger experiment, trigger output as shown in Figure 9, show described micro-acceleration gauge response better by oscillograph recording, and comparatively stable.

Proved absolutely that the high electron mobility transistor (HEMT) that is provided with on the micro-acceleration gauge of the present invention has tangible power electric conversion properties.

4, micro-acceleration gauge is carried out the sensory characteristic experiment: micro-acceleration gauge is fixed on the shaking table of VR8500 shaking table test macro, apply sinusoidal excitation signal by shaking table, test the output signal of micro-acceleration gauge shown in Figure 10,11, Figure 10 is the voltage output signal before the filtering, and Figure 11 is filtered voltage output signal; And the linear fit that obtains output of micro-acceleration gauge voltage and acceleration concerns, as shown in figure 12, can find: near all swings linear fit line of test point of micro-acceleration gauge output, show the better linearity degree, the sensitivity of micro-acceleration gauge is 10.68mV/g after the match.Prove absolutely that micro-acceleration gauge of the present invention can realize highly sensitive detection.

The present invention effectively utilizes the power electricity switching mechanism of high electron mobility transistor (HEMT), realized the application of high electron mobility transistor (HEMT) on micro-acceleration gauge, characteristics such as that micro-acceleration gauge of the present invention has shown in process of the test is highly sensitive, the linearity is good can adapt to the actual needs of micro-acceleration gauge application fully.

Description of drawings

Fig. 1 is a process for machining and manufacturing process flow diagram of the present invention;

Fig. 2 is the sem photograph of high electron mobility transistor (HEMT) on the micro-acceleration gauge of the present invention;

Fig. 3 is the output characteristic curve of high electron mobility transistor (HEMT) on the micro-acceleration gauge of the present invention;

Fig. 4 is the transfer characteristic curve of high electron mobility transistor (HEMT) on the micro-acceleration gauge of the present invention;

Fig. 5 be on the micro-acceleration gauge of the present invention high electron mobility transistor (HEMT) at the I-V family curve comparison diagram of Z directional acceleration during for ± 1g;

Fig. 6 be high electron mobility transistor (HEMT) drain voltage and piezoresistance coefficient on the micro-acceleration gauge of the present invention graph of a relation (grid voltage for-1.7V);

Fig. 7 is an I-V family curve comparison diagram before and after the micro-acceleration gauge pressurization of the present invention;

Fig. 8 is a transfer characteristic curve comparison diagram before and after the micro-acceleration gauge pressurization of the present invention;

Fig. 9 triggers the triggering output map that experiment obtains for micro-acceleration gauge of the present invention carries out static pressurization;

Figure 10 is the preceding voltage output signal diagram of the filtering of micro-acceleration gauge of the present invention;

Figure 11 is a voltage output signal diagram after the filtering of micro-acceleration gauge of the present invention;

Figure 12 is the linear fit graph of a relation of micro-acceleration gauge voltage output of the present invention and acceleration;

Among the figure: the 1-GaAs substrate; The 2-film; The 3-drain electrode; The 4-source electrode; The 5-groove; The 6-grid; 7-Si ₃N ₄Passivation layer; The 8-photoresist; 9-double base metal level; The 10-photoresist; 11-bridge connected in star; The 12-Au layer; The 13-air bridges; The peripheral pedestal of 14-; The 15-semi-girder; The 16-mass; The 17-high electron mobility transistor (HEMT).

Embodiment

Based on the micro-acceleration gauge of high electron mobility transistor (HEMT), adopt the following steps processing and manufacturing:

(1), uses molecular beam epitaxy technique grows material layer structures as shown in table 1 below on GaAs substrate 1 film 2: shown in c among Fig. 1

Table 1

(2), use the micro electro mechanical device process technology and process high electron mobility transistor (HEMT) as follows:

A, according to the layout of micro-acceleration gauge structure to be processed, remove all films except that required processing high electron mobility transistor (HEMT) position film 2 on the GaAs substrate 1 with etching technics; For example: the micro-acceleration gauge of processing four limits, four girder constructions, then need to keep four films that are used to process high electron mobility transistor (HEMT), and the film retention position is being " ten " word distribution (being that the film retention position is distributed on four ends of " a ten " font) on the GaAs substrate, shown in a among Fig. 1; And the work sheet cantilever beam structure then only keeps monolithic films to get final product on the GaAs substrate;

B, on GaAs substrate 1, respectively keep the film place and process high electron mobility transistor (HEMT) respectively:

B1, at first adopt photoetching process to process the source electrode 4 of high electron mobility transistor (HEMT) on the ohmic contact layer n-GaAs surface of described film and 3 the Ohmic contact figure of draining, shown in b1-1 among Fig. 1, adopt electron beam evaporation process to form then on ohmic contact layer n-GaAs surface

Thick Au/Ge/Ni overlayer, after after peeling off cleaning, with 400 ℃ of high temperature quick alloy in 60s, realize source electrode 4, drain electrode 3 metallization of transistor HEMT, make between source electrode 4, drain electrode 3 and the ohmic contact layer n-GaAs surface of described film of transistor HEMT and form good Ohmic contact, wherein, the source electrode of high electron mobility transistor (HEMT) is provided with for separating, promptly constitute by two separated source 4, shown in b4-1 among Fig. 1, and the orientation of two separated source 4 is parallel with drain electrode 3, and shown in b1-2 among Fig. 1, b4-1 is the right view of b1-2 among Fig. 1;

B2, on source electrode 4 and the film between 3 of draining, process and drain parallel and run through the groove 5 of whole film, and groove 5 is groove bottom with the schottky contact layer n-AlGaAs surface of film, shown in b2-1 among Fig. 1 with etching technics; In the middle of groove 5 bottom lands, process the grid groove with photoetching process then along groove 5 directions, and in grid groove process, detection resources is leaked the saturation current of two interpolars in real time, the saturation current that leaks two interpolars until the source reaches required value, obtain required grid groove, adopt electron beam evaporation process in groove surfaces, grid groove, to form subsequently

Thick Ti/Pt/Au overlayer, form grid 6 at grid groove place to peel off method, realize the gate metalized of transistor HEMT, shown in b2-2 among Fig. 1, the good Schottky barrier of formation between the grid that makes transistor HEMT and the schottky contact layer n-AlGaAs of described film;

B3, processing on high electron mobility transistor (HEMT) source electrode 4, drain electrode 3, the film of grid 6 with 230 ℃ of temperature deposits with the PECVD sedimentation

Thick Si ₃N ₄Passivation layer 7 is shown in b3-1 among Fig. 1, then with the described Si of photoetching process etching ₃N ₄Passivation layer 7 makes Si ₃N ₄Passivation layer 7 zones only cover source electrode 4 and drain between 3 and the source electrode 4 and 3 edges over against side that drain, shown in b3-2 among Fig. 1;

1., covering Si b4, processing connects the air bridges 13 of two separated source between two separated source 4: ₃N ₄Coating photoresist 8 on the film of passivation layer 7, and to use that photoetching process forms directly over two separated source 4 be two bridge pier shape grooves of groove bottom with two separated source, 4 upper surfaces respectively, adopts electron beam evaporation process or sputtering technology to cover in the surperficial and bridge pier shape groove at photoresist then

Thick TiAu or TiW double base metal level 9 are shown in b4-2 among Fig. 1; 2., at TiAu or TiW double base metal level 9 surface applied photoresists 10, using photoetching process once more, to form with TiAu or TiW double base metal level directly over two separated source be the bridge connected in star 11 of groove bottom, shown in b4-3 among Fig. 1, adopt electroplating technology on TiAu or TiW double base metal level 9, to electroplate the thick Au layer 12 of 2～5 μ m then, shown in b4-4 among Fig. 1; 3., use the photoresist 10 of organic solvent dissolution TiAu or TiW double base metal level 9 tops, erode all TiAu or TiW double base metal level outside Au layer below TiAu or the TiW double base metal level 9 then, use photoresist 8 remaining on the described film of organic solvent dissolution at last, promptly obtain described air bridges 13, shown in b4-5 among Fig. 1, finish the high electron mobility transistor (HEMT) processing on the described film;

(3), use the micro electro mechanical device process technology and process the micro-acceleration gauge structure as follows: shown in d among Fig. 1, use etching technics and GaAs substrate 1 is etched into by peripheral pedestal 14, semi-girder 15 and by 15 of semi-girders is suspended from the micro-acceleration gauge structure that the mass 16 of peripheral pedestal 14 central authorities constitutes, and make the described film that is processed with high electron mobility transistor (HEMT) 17 be positioned at the junction of semi-girder 15 and peripheral pedestal 14.

Claims (1)

1. job operation based on the micro-acceleration gauge of high electron mobility transistor (HEMT) is characterized in that adopting the following steps processing and manufacturing:

(1), use molecular beam epitaxy technique grows material layer structures as shown in table 1 below on GaAs substrate (1) film (2):

Table 1

(2), use the micro electro mechanical device process technology and process high electron mobility transistor (HEMT) as follows:

A, according to the layout of micro-acceleration gauge structure to be processed, remove GaAs substrate (1) with etching technics and go up all films except that required processing high electron mobility transistor (HEMT) position film (2);

B, on GaAs substrate (1), respectively keep the film place and process high electron mobility transistor (HEMT) respectively:

B1, at first adopt photoetching process to process the source electrode (4) of high electron mobility transistor (HEMT) and the Ohmic contact figure of drain electrode (3) on the ohmic contact layer n-GaAs surface of described film, adopt electron beam evaporation process to form then on ohmic contact layer n-GaAs surface

Thick Au/Ge/Ni overlayer, after after peeling off cleaning, with 400 ℃ of high temperature quick alloy in 60s, realize source electrode (4), drain electrode (3) metallization of transistor HEMT, make between the ohmic contact layer n-GaAs surface of source electrode (4), drain electrode (3) and described film of transistor HEMT and form good Ohmic contact, wherein, the source electrode of high electron mobility transistor (HEMT) is provided with for separating, promptly constitute, and the orientation of two separated source (4) is parallel with drain electrode (3) by two separated source (4);

B2, process on the film between (3) at source electrode (4) and drain electrode and drain parallel and run through the groove (5) of whole film, and groove (5) is a groove bottom with the schottky contact layer n-AlGaAs surface of film with etching technics; In the middle of groove (5) bottom land, process the grid groove with photoetching process then along groove (5) direction, and in grid groove process, detection resources is leaked the saturation current of two interpolars in real time, the saturation current that leaks two interpolars until the source reaches required value, obtain required grid groove, adopt electron beam evaporation process in groove surfaces, grid groove, to form subsequently

Thick Ti/Pt/Au overlayer forms grid (6) to peel off method at grid groove place, realize the gate metalized of transistor HEMT, the good Schottky barrier of formation between the grid that makes transistor HEMT and the schottky contact layer n-AlGaAs of described film;

B3, with the PECVD sedimentation on the film that processes high electron mobility transistor (HEMT) source electrode (4), drain electrode (3), grid (6) with 230 ℃ of temperature deposits Thick Si ₃N ₄Passivation layer (7) is then with the described Si of photoetching process etching ₃N ₄Passivation layer (7) makes Si ₃N ₄Passivation layer (7) zone only covers between source electrode (4) and the drain electrode (3) and the source electrode (4) and (3) edge over against side that drains;

1., covering Si b4, processing connects the air bridges (13) of two separated source between two separated source (4): ₃N ₄Apply photoresist (8) on the film of passivation layer (7), and to use that photoetching process forms directly over two separated source (4) be two bridge pier shape grooves of groove bottom with two separated source (4) upper surface respectively, adopts electron beam evaporation process or sputtering technology to cover in the surperficial and bridge pier shape groove at photoresist then

Thick TiAu or TiW double base metal level (9); 2., at TiAu or TiW double base metal level (9) surface applied photoresist (10), using once more that photoetching process forms directly over two separated source with TiAu or TiW double base metal level is the bridge connected in star (11) of groove bottom, adopts electroplating technology to go up at TiAu or TiW double base metal level (9) then and electroplates the thick Au layer (12) of 2～5 μ m; 3., with the photoresist (10) above organic solvent dissolution TiAu or the TiW double base metal level (9), erode Au layer below TiAu or outer all TiAu or the TiW double base metal level of TiW double base metal level (9) then, use photoresist (8) remaining on the described film of organic solvent dissolution at last, promptly obtain described air bridges (13), finish high electron mobility transistor (HEMT) (17) processing on the described film;

(3), use the micro electro mechanical device process technology and process the micro-acceleration gauge structure as follows:

Use etching technics and GaAs substrate (1) is etched into by peripheral pedestal (14), semi-girder (15) and by semi-girder (15) is suspended from the micro-acceleration gauge structure that the mass (16) of peripheral pedestal (14) central authorities constitutes, and make the described film that is processed with high electron mobility transistor (HEMT) (17) be positioned at the junction of semi-girder (15) and peripheral pedestal (14).

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