CN101609110B - Signal extraction method of resonant tunneling piezoresistive micro-accelerometer - Google Patents
Signal extraction method of resonant tunneling piezoresistive micro-accelerometer Download PDFInfo
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- CN101609110B CN101609110B CN2009100749387A CN200910074938A CN101609110B CN 101609110 B CN101609110 B CN 101609110B CN 2009100749387 A CN2009100749387 A CN 2009100749387A CN 200910074938 A CN200910074938 A CN 200910074938A CN 101609110 B CN101609110 B CN 101609110B
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Abstract
The invention relates to signal extraction of an MEMS micro-accelerometer, in particular to a signal extraction method of a resonant tunneling piezoresistive micro-accelerometer, further optimizing the resonant tunneling piezoresistive micro-accelerometer. The extraction method comprises the following steps: (1) in the absence of ambient pressure, detecting the reference voltage corresponding to the peak point or valley point in the negative impedance region of an I-V characteristic curve of a resonant tunneling diode (RTD), the resonant tunneling microstructure of the resonant tunneling piezoresistive micro-accelerometer; (2) according to the reference voltage obtained in the step (1), resetting the initial voltage applied on the RTD reasonably; (3) detecting the variation of the voltage value corresponding to the peak point or valley point in the negative impedance region of the I-V characteristic curve of the RTD, the resonant tunneling microstructure of the resonant tunneling piezoresistive micro-accelerometer in real time. The resonant tunneling piezoresistive micro-accelerometer adopting the signal extraction method of the invention enjoys high sensitivity, good frequency response characteristics and good linearity of the output signals.
Description
Technical field
The present invention relates to the signal extraction of MEMS micro-acceleration sensor, specifically is a kind of method for extracting signal of resonant tunneling piezoresistive micro-accelerometer.
Background technology
Resonant tunneling piezoresistive micro-accelerometer with resonance tunnel-through microstructure-resonance tunnel-through diode (RTD) as responsive conversion element, at present, Jie that the signal extraction of resonant tunneling piezoresistive micro-accelerometer is based on resonance tunnel-through diode sees piezoresistive effect, under the ambient pressure effect, drift can take place in the I-V family curve (as shown in Figure 1) of resonance tunnel-through diode, the resistance value of resonance tunnel-through diode changes, and uses the change in electric amount that Wheatstone bridge extracts resonance tunnel-through diode.
Shown in Fig. 2,3, increase along with force value, comparatively significantly skew has taken place in the I-V family curve of resonance tunnel-through microstructure-resonance tunnel-through diode, from the quantum mechanics angle analysis, the main cause that produces this phenomenon is: 1. theoretically as can be known, the AlAs/GaAs resonance tunnel-through microstructure that has sub-trap In0.1Ga0.9As has built in field, according to the power coupling effect, under the mechanical signal effect, produce stress distribution in the nano belt structure; The variation of stress causes the variation of built in field under the certain condition; The variation of built in field causes the variation of tunnelling current, and the variation of tunnelling current is presented as the skew of curve on the I-V characteristic; 2. exert pressure and cause the first quantum level E in the microstructure potential well
0Drift, the bias voltage of corresponding tunnelling current correspondence drifts about; 3. because AlAs is different with the piezoelectric constant of GaAs material, stress can produce polarization charge at the heterojunction boundary place, the distribution influence of polarization charge satisfy the needed bias value of tunnelling condition.
And obtain from the quantum theory analysis, under different bias effects, the first quantized level E in the resonance tunnel-through microstructure potential well
0Drift about, work as E
0=E
CThe time (E
CBe energy level at the bottom of the emitter conduction band), tunnelling current reaches maximal value, is peak value; Work as E
0When reaching minimum value, also minimum by the tunnelling current of double potential barrier, be valley; The first quantized level E in the potential well
0Drift make the electric current of extreme value place (peak value or peak valley) that maximum variation take place, cause changes in resistance also maximum, by sensitivity formula Δ R
i/ (R * σ) as can be known, maximum Jie sees pressure drag sensitivity and must appear at peak value or peak valley position, and does not change with the variation of stress value.Sensitivity formula Δ R
i/ (among the R * σ), σ is the size to resonance tunnel-through diode institute stress application, Δ R
iBe the variable quantity of every kind of situation low-resonance tunnel-through diode resistance value with respect to initial value, R is the resonance tunnel-through diode initial resistivity value.
Summary of the invention
The present invention based on the power electric coupling characteristic of its responsive conversion element-resonance tunnel-through diode (RTD), provides a kind of method for extracting signal of resonant tunneling piezoresistive micro-accelerometer in order further to optimize resonant tunneling piezoresistive micro-accelerometer.
The present invention adopts following technical scheme to realize: the method for extracting signal of resonant tunneling piezoresistive micro-accelerometer, and extraction step is as follows:
1., under no ambient pressure effect, detect peak point or valley point corresponding voltage value in resonance tunnel-through microstructure-resonance tunnel-through diode (RTD) I-V family curve negative impedance region with resonant tunneling piezoresistive micro-accelerometer, detect step and be:
A, in the voltage range that comprises resonance tunnel-through diode I-V family curve negative impedance region, resonance tunnel-through diode is applied voltage, and applies voltage and begin to increase progressively by the lower limit of voltage range, perhaps the upper limit by voltage range begins to successively decrease;
B, in the increasing or decreasing process that resonance tunnel-through diode is applied voltage, the oscillator signal of extract real-time resonance tunnel-through diode, when extracting oscillator signal (when resonance tunnel-through diode produces vibration), determine to cause the magnitude of voltage of resonance tunnel-through diode vibration, this magnitude of voltage is decided to be reference voltage, and stop resonance tunnel-through diode being continued to apply voltage, described reference voltage promptly be with resonance tunnel-through diode I-V family curve negative impedance region in peak point or valley point corresponding voltage value;
2., the reference voltage that 1. obtains according to step, again rationally set the starting potential that puts on the resonance tunnel-through diode, the setting of starting potential will guarantee: having under the ambient pressure effect, with step 1. in after the corresponding peak point of reference voltage or the valley point skew, peak point or valley point skew back corresponding voltage value are being starting point with the starting potential, are applying in the voltage regime of voltage gradient trend-increasing or decreasing in 1. set by step;
3., in real time detect the interior peak point of resonance tunnel-through microstructure-resonance tunnel-through diode I-V family curve negative impedance region of resonant tunneling piezoresistive micro-accelerometer or the variable quantity of valley point corresponding voltage value, the detection step is:
C, apply the gradual change trend-increasing or decreasing of voltage in 1. set by step, restart resonance tunnel-through diode is applied voltage with the starting potential that 2. step is set, the oscillator signal of extract real-time resonance tunnel-through diode, when extracting oscillator signal, determine to cause that resonance tunnel-through diode produces the current magnitude of voltage of vibration, stop simultaneously resonance tunnel-through diode is continued to apply voltage;
D, ask for the voltage difference of reference voltage in current magnitude of voltage and the step 1, this voltage difference be to extract with the relevant variable quantity of ambient pressure size.
Method for extracting signal of the present invention is based on: owing to have electric charge accumulation effect in the quantum well of resonance tunnel-through microstructure-resonance tunnel-through diode (RTD), the III-V family semiconductor material that resonance tunnel-through diode is used all has piezoelectric property, under the ambient pressure effect, resonance tunnel-through microstructure-resonance tunnel-through diode layers of material will accumulate polarization charge at the interface, produce built in field, thereby influence the I-V family curve of resonance tunnel-through diode, resonance tunnel-through diode I-V family curve is offset.Method for extracting signal of the present invention promptly is by detecting the side-play amount of characteristic crest voltage of resonance tunnel-through diode I-V or valley point voltage, test the variation of built in field in the resonance tunnel-through diode that ambient pressure causes, thus the quantitative relation of the characteristic crest voltage of resonance tunnel-through diode I-V or valley point voltage side-play amount and ambient pressure.
Resonant tunneling piezoresistive micro-accelerometer with existing signal extraction technology by the Wheatstone bridge realization, method for extracting signal of the present invention carries out output voltage linearity degree, Frequency Response test respectively;
1, the test of resonant tunneling piezoresistive micro-accelerometer output voltage linearity degree:
A, during with existing techniques in realizing signal extraction, the output of regulating stabilized voltage supply makes resonance tunnel-through micro-acceleration sensor both end voltage be stabilized in negative impedance region (non-platform area) and non-negative impedance region respectively, regulate Wheatstone bridge and make it balance, the initial value of output voltage is zero, resonant tunneling piezoresistive micro-accelerometer is fixed on the shaking table, the frequency of setting the shaking table sinusoidal excitation signal is 320Hz, change the vibration acceleration of shaking table, test is under different accekerations, the output signal of resonant tunneling piezoresistive micro-accelerometer, result are as shown in Figure 4;
B, when realizing signal extraction with method for extracting signal of the present invention, resonant tunneling piezoresistive micro-accelerometer is fixed on the shaking table, the frequency of setting the shaking table sinusoidal excitation signal is 320Hz, change the vibration acceleration of shaking table, test is under different accekerations, the output signal of resonant tunneling piezoresistive micro-accelerometer, result are as shown in Figure 5;
Comparison diagram 4 and Fig. 5 adopt the output voltage linearity degree of the resonant tunneling piezoresistive micro-accelerometer of method for extracting signal of the present invention will obviously be better than adopting existing Wheatstone bridge to realize the output voltage linearity degree of the resonant tunneling piezoresistive micro-accelerometer of signal extraction as can be seen.
2, the test of resonant tunneling piezoresistive micro-accelerometer Frequency Response:
A, during with existing techniques in realizing signal extraction, the output of regulating stabilized voltage supply makes resonance tunnel-through micro-acceleration sensor both end voltage be stabilized in negative impedance region (non-platform area) and non-negative impedance region respectively, regulate Wheatstone bridge and make it balance, the initial value of output voltage is zero, resonant tunneling piezoresistive micro-accelerometer is fixed on the shaking table, set the vibration acceleration g=10g of shaking table, change the sinusoidal excitation signal frequency of shaking table, test is under different frequency, the output voltage of resonant tunneling piezoresistive micro-accelerometer, the result is as shown in Figure 6; When the figure medium frequency is 2500Hz near the resonant frequency of micro-acceleration sensor.
B, when realizing signal extraction with method for extracting signal of the present invention, resonant tunneling piezoresistive micro-accelerometer is fixed on the shaking table, set the vibration acceleration g=10g of shaking table, change the sinusoidal excitation signal frequency of shaking table, test is under different frequency, the output voltage of resonant tunneling piezoresistive micro-accelerometer, the result is as shown in Figure 7;
Comparison diagram 6 and Fig. 7 are as can be seen, adopt the frequency response curve of resonant tunneling piezoresistive micro-accelerometer of method for extracting signal of the present invention Paint Gloss, in the response voltage value of characteristic frequency than adopting existing Wheatstone bridge to realize that the response voltage value of resonant tunneling piezoresistive micro-accelerometer of signal extraction is bigger.
In addition, the resonant tunneling piezoresistive micro-accelerometer that adopts method for extracting signal of the present invention is carried out sensitivity test: resonant tunneling piezoresistive micro-accelerometer is fixed on the shaking table, the output of regulating stabilized voltage supply makes the micro-acceleration sensor both end voltage be stabilized in negative impedance region and non-negative impedance region, set the vibration acceleration g=10g of shaking table, sinusoidal excitation signal frequency f=170Hz, test is under different bias voltages, the output voltage of resonant tunneling piezoresistive micro-accelerometer, draw output voltage sensitivity and biased relation curve, as shown in Figure 8;
As can be seen from Figure 8, the sensitivity of micro-acceleration sensor highly sensitive a lot of than non-negative impedance region when bias voltage is added to negative impedance region, and highly sensitive at the remolding sensitivity peak value place at negative impedance region valley place, the sensitivity of platform area part is lower in the negative impedance region, and peak response can reach 560mV/g at valley point voltage 0.618V place.
From the quantum theory analysis, under different bias effects, the first quantized level E in resonance tunnel-through microstructure-resonance tunnel-through diode potential well
0Drift about, work as E
0=E
cThe time (E
cBe energy level at the bottom of the emitter conduction band), tunnelling current reaches maximal value; Work as E
0When reaching minimum value, also minimum by the tunnelling current of double potential barrier.When applying pumping signal to micro-acceleration sensor, when the resonance tunnel-through microstructure is subjected to stress, under fixed-bias transistor circuit, the first quantized level E in the potential well
0Drift about, this makes the electric current of extreme value place (peak value and valley) that maximum variation take place, and corresponding resistance change is also maximum, promptly has maximum Jie to see pressure drag sensitivity in the peak value and the valley position of negative impedance region.Thus, also verified the advantage of method for extracting signal of the present invention once more.
Adopt resonant tunneling piezoresistive micro-accelerometer highly sensitive of method for extracting signal of the present invention, good frequency response, the linearity of output signal is good.
Description of drawings
Fig. 1 is the I-V family curve of resonance tunnel-through diode (RTD);
Fig. 2 is the I-V family curve deflection graph of resonance tunnel-through diode when being subjected to different stress;
Fig. 3 is the partial enlarged drawing of Fig. 2;
The output voltage (negative impedance region) and relationship with acceleration curve of Fig. 4 for adopting the resonant tunneling piezoresistive micro-accelerometer that has the signal extraction technology now;
Fig. 5 is the output voltage and the relationship with acceleration curve of the resonant tunneling piezoresistive micro-accelerometer of employing method for extracting signal of the present invention;
Fig. 6 is for adopting the frequency response curve of the resonant tunneling piezoresistive micro-accelerometer that has the signal extraction technology now;
Fig. 7 is the frequency response curve of the resonant tunneling piezoresistive micro-accelerometer of employing method for extracting signal of the present invention;
Fig. 8 is the output voltage sensitivity and biased relation curve of the resonant tunneling piezoresistive micro-accelerometer of employing method for extracting signal of the present invention.
Embodiment
The method for extracting signal of resonant tunneling piezoresistive micro-accelerometer, extraction step is as follows:
1., under no ambient pressure effect, detect peak point or valley point corresponding voltage value in resonance tunnel-through microstructure-resonance tunnel-through diode (RTD) I-V family curve negative impedance region with resonant tunneling piezoresistive micro-accelerometer, detect step and be:
A, in the voltage range that comprises resonance tunnel-through diode I-V family curve negative impedance region, resonance tunnel-through diode is applied voltage, and applies voltage and begin to increase progressively by the lower limit of voltage range, perhaps the upper limit by voltage range begins to successively decrease;
B, in the increasing or decreasing process that resonance tunnel-through diode is applied voltage, the oscillator signal of extract real-time resonance tunnel-through diode, when extracting oscillator signal (when resonance tunnel-through diode produces vibration), determine to cause the magnitude of voltage of resonance tunnel-through diode vibration, this magnitude of voltage is decided to be reference voltage, and stop resonance tunnel-through diode being continued to apply voltage, described reference voltage promptly be with resonance tunnel-through diode I-V family curve negative impedance region in peak point or valley point corresponding voltage value;
2., the reference voltage that 1. obtains according to step, again rationally set the starting potential that puts on the resonance tunnel-through diode, the setting of starting potential will guarantee: having under the ambient pressure effect, with step 1. in after the corresponding peak point of reference voltage or the valley point skew, peak point or valley point skew back corresponding voltage value are being starting point with the starting potential, are applying in the voltage regime of voltage gradient trend-increasing or decreasing in 1. set by step;
3., in real time detect the interior peak point of resonance tunnel-through microstructure-resonance tunnel-through diode I-V family curve negative impedance region of resonant tunneling piezoresistive micro-accelerometer or the variable quantity of valley point corresponding voltage value, the detection step is:
C, apply the gradual change trend-increasing or decreasing of voltage in 1. set by step, restart resonance tunnel-through diode is applied voltage with the starting potential that 2. step is set, the oscillator signal of extract real-time resonance tunnel-through diode, when extracting oscillator signal, determine to cause that resonance tunnel-through diode produces the current magnitude of voltage of vibration, stop simultaneously resonance tunnel-through diode is continued to apply voltage;
D, ask for the voltage difference of reference voltage in current magnitude of voltage and the step 1, this voltage difference be to extract with the relevant variable quantity of ambient pressure size.
Claims (1)
1. the method for extracting signal of a resonant tunneling piezoresistive micro-accelerometer is characterized in that extraction step is as follows:
1., under no ambient pressure effect, detect peak point or valley point corresponding voltage value in the resonance tunnel-through microstructure-resonance tunnel-through diode I-V family curve negative impedance region with resonant tunneling piezoresistive micro-accelerometer, detect step and be:
A, in the voltage range that comprises resonance tunnel-through diode I-V family curve negative impedance region, resonance tunnel-through diode is applied voltage, and applies voltage and begin to increase progressively by the lower limit of voltage range, perhaps the upper limit by voltage range begins to successively decrease;
B, in the increasing or decreasing process that resonance tunnel-through diode is applied voltage, the oscillator signal of extract real-time resonance tunnel-through diode, when extracting oscillator signal, determine to cause the magnitude of voltage of resonance tunnel-through diode vibration, this magnitude of voltage is decided to be reference voltage, and stop resonance tunnel-through diode being continued to apply voltage, described reference voltage promptly be with resonance tunnel-through diode I-V family curve negative impedance region in peak point or valley point corresponding voltage value;
2., the reference voltage that 1. obtains according to step, again rationally set the starting potential that puts on the resonance tunnel-through diode, the setting of starting potential will guarantee: having under the ambient pressure effect, with step 1. in after the corresponding peak point of reference voltage or the valley point skew, peak point or valley point skew back corresponding voltage value are being starting point with the starting potential, are applying in the voltage regime of voltage gradient trend-increasing or decreasing in 1. set by step;
3., in real time detect the interior peak point of resonance tunnel-through microstructure-resonance tunnel-through diode I-V family curve negative impedance region of resonant tunneling piezoresistive micro-accelerometer or the variable quantity of valley point corresponding voltage value, the detection step is:
C, apply the gradual change trend-increasing or decreasing of voltage in 1. set by step, restart resonance tunnel-through diode is applied voltage with the starting potential that 2. step is set, the oscillator signal of extract real-time resonance tunnel-through diode, when extracting oscillator signal, determine to cause that resonance tunnel-through diode produces the current magnitude of voltage of vibration, stop simultaneously resonance tunnel-through diode is continued to apply voltage;
D, ask for current magnitude of voltage and step 1. in the voltage difference of reference voltage, this voltage difference be to extract with the relevant variable quantity of ambient pressure size.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5668319A (en) * | 1994-02-07 | 1997-09-16 | The Regents Of The University Of California | Micromachined accelerometer |
| CN1632486A (en) * | 2004-11-19 | 2005-06-29 | 清华大学 | Resonant tunneling micro mechanical force sensor and method for manufacturing the same |
| CN1752757A (en) * | 2005-09-12 | 2006-03-29 | 中北大学 | Resonance tunnel through pressure resistance type micro acceleration meter |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5668319A (en) * | 1994-02-07 | 1997-09-16 | The Regents Of The University Of California | Micromachined accelerometer |
| CN1632486A (en) * | 2004-11-19 | 2005-06-29 | 清华大学 | Resonant tunneling micro mechanical force sensor and method for manufacturing the same |
| CN1752757A (en) * | 2005-09-12 | 2006-03-29 | 中北大学 | Resonance tunnel through pressure resistance type micro acceleration meter |
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