CN102542077B - Parameter extraction method of AlGaN/GaN HEMT small-signal model - Google Patents

Abstract

The present invention relates to a kind of parameter extracting methods of AlGaN/GaN HEMT small-signal model, belong to technical field of integrated circuits. The parameter extracting method is the improvement carried out on the basis of traditional parameter extracting method, takes open circuit that embedding figure is gone to carry out the extraction of peripheral parasitic parameter, introduces grid end Schottky resistance Dead resistance and inductance are extracted, drain terminal delay factor is introduced Internal intrinsic parameters are extracted, guarantee that extracted parameter is all positive value, and have physical significance, so as to improve S11 and S22 in the S parameter of small-signal parameter, during parameter extraction With Two are often easy to appear negative value, With Introducing substantially eliminate them and a possibility that negative value occur, these are improved so that the parameter accuracy extracted has large increase.

Description

The parameter extracting method of AlGaN/GaN HEMT small-signal model

Technical field

The present invention relates to a kind of parameter extracting method, relate in particular to a kind of parameter extracting method of AlGaN/GaN HEMT small-signal model, belong to technical field of integrated circuits.

Background technology

AlGaN/GaN HEMT small-signal model is to set up the basis of large-signal model, and whether accurately the extracting method of small-signal model parameter is to determine small-signal model principal element.Small-signal model parameter is determined by small-signal model topological structure, comprises peripheral parasitic parameter and inner intrinsic parameters.Generally, peripheral parasitic parameter is linear element, namely with the change of extraneous bias voltage and frequency, does not change, and mainly comprises series connection dead resistance R _g, R _d, R _s; Series connection stray inductance L _g, L _d, L _s, peripheral stray capacitance C _pg, C _pdand C _pgd.Inner intrinsic parameters is nonlinear element, can change along with the change of extraneous bias voltage and frequency, mainly comprises inner gate capacitance C _gs, C _gd, source-drain current source I _dsby mutual conductance g _mwith its delay factor τ _mcharacterize source leakage conductance g _dswith its delay factor τ _ds.Drain-source capacitor C _dswith grid source channel resistance R _ialong with the variation of extraneous bias voltage is very little, can think linear dimensions.The in the situation that of small signal driving, the variation of inner intrinsic elements also can be equivalent to the element of linear change, and all parameters of small-signal model have definite numerical value under fixing bias state like this, is used for characterizing the high frequency characteristics of device under particular state.

Small-signal model is relevant with the topological structure of device, and the topological structure of device has characterized the physical characteristics of device itself, that is to say that each small-signal model parameter has specific physical significance, physical arrangement feature and the specific physical interpretation that so just can reflect device, these also with device fabrication processes in each step process parameter connect closely, the variation of physical parameter can cause the change of small-signal model parameter, and small-signal model parameter also can instruct processing step, improve the structure of device, instruct the direction of device improvement in performance, small-signal model has reflected the high frequency characteristics under certain bias, also be the steps necessary of setting up large-signal model, so the extraction of small-signal model parameter is also related to the accuracy of large-signal model, and large-signal model also can reflect small-signal behaviour under certain bias.

For GaN HEMT device, owing to being new material and device, from traditional some different place of processing step, the monitoring of the technique accuracy of each step is very important, and after element manufacturing completes, equivalent-circuit model can general token device property, reflection device performance, the device various characteristics in this technological process of total evaluation.Small-signal equivalent circuit can emulation certain bias state in circuit S parameter, obtain the gain of device and circuit, can be for application such as design small signal amplifiers.So to the research of small-signal equivalent circuit highly significant, so the extracting method of small-signal equivalent circuit parameter just becomes particularly important.

Summary of the invention

The object of the invention is for the physical topology of device and equivalent circuit parameter are connected, simultaneously, also for the foundation of the large-signal model of device provides necessary basis, provide a kind of parameter extracting method of AlGaN/GaN HEMT small-signal model.

The technical scheme that the present invention solves the problems of the technologies described above is as follows: a kind of parameter extracting method of AlGaN/GaN HEMT small-signal model comprises:

Step 10: measure peripheral open circuit and remove the scattering parameter S of embedding circuit, and its conversion is obtained to admittance parameter Y, thereby calculate peripheral stray capacitance C _pg, C _pdand C _pgdnumerical value, described peripheral open circuit goes embedding circuit to comprise peripheral stray capacitance C _pg, C _pdand C _pgd, described peripheral stray capacitance C _pgdseries connection C _pgand C _pdbetween;

Step 20: at V _gs> 0, V _dsunder the bias state of=0V, select the gate voltage value of two groups of AlGaN/GaN HEMT devices to be respectively V _gs1and V _gs2, test obtain two groups respectively with two groups of gate voltage value current value I corresponding and that be less than 10mA _gs1and I _gs2, current value I _gs1and I _gs2size more approaching, then measure gate voltage value and be respectively V _gs1and V _gs2time S parameter, and its conversion is obtained to impedance parameter Z, then calculates the numerical value of series connection dead resistance and series connection stray inductance;

Step 30: measure the S parameter of AlGaN/GaN HEMT device under bias state, remove the peripheral stray capacitance C calculating in step 10 _pg, C _pdand C _pgdthe series connection dead resistance R obtaining with step 20 _g, R _d, R _swith series connection stray inductance L _g, L _d, L _s, obtain the intrinsic S parameter of inner parameter, and its conversion obtained to Y parameter, then calculate the inside intrinsic parameters gate capacitance C under bias state _gs, C _gd, mutual conductance g _mand delay factor τ _m, source leakage conductance g _dsand drain terminal delay factor τ _ds, drain-source capacitor C _dswith grid source channel resistance R _inumerical value.

On the basis of technique scheme, the present invention can also do following improvement.

Further, described step 10 calculates peripheral stray capacitance C _pg, C _pdand C _pgdthe process of numerical value comprise: S parameter transformation is obtained to Y parameter, and according to formula (1)～(3)

Im(Y ₁₁)＝ω(C _pg+C _pgd) (1)

Im(Y ₁₂)＝Im(Y ₂₁)＝-ωC _pgd (2)

Im(Y ₂₂)＝ω(C _pd+C _pgd) (3)

Calculate peripheral stray capacitance C _pg, C _pdand C _pgdnumerical value be respectively

$C_{\mathrm{pgd}}=-\frac{\mathrm{Im}\left(Y_{21}\right)+\mathrm{Im}\left(Y_{12}\right)}{\mathrm{\ω}},C_{\mathrm{pg}}=\frac{\mathrm{Im}\left(Y_{11}\right)}{\mathrm{\ω}}-C_{\mathrm{pgd}},C_{\mathrm{pd}}=\frac{\mathrm{Im}\left(Y_{22}\right)}{\mathrm{\ω}}-C_{\mathrm{pgd}}.$

Further, in described step 20, the gate voltage value of optional two groups of AlGaN/GaN HEMT is all greater than the Schottky voltage of AlGaN/GaN HEMT, and current value corresponding to gate voltage value of two groups of AlGaN/GaN HEMT is all less than 10mA simultaneously.

Further, described step 20 is at V _gs> 0, V _dsunder the bias state of=0V, the equivalent electrical circuit of AlGaN/GaN HEMT device comprises series connection dead resistance R _g, R _dand R _s, series connection stray inductance L _g, L _dand L _s, a plurality of grid end distributed resistance Δ R _gs, a plurality of grid end distributed capacitance Δ C _g, a plurality of raceway groove distributed resistance Δ R _chwith a plurality of raceway groove distributed capacitance Δ C _ds, wherein, grid end distributed resistance Δ R _gswith grid end distributed capacitance Δ C _gbe in parallel and form the grid end unit in parallel that distributes, a plurality of described grid ends distribute unit in parallel parallel with one another after with the dead resistance R that connects _gbe in series, described series connection dead resistance R _gwith series connection stray inductance L _gbe in series, raceway groove distributed resistance Δ R _chwith raceway groove distributed capacitance Δ C _dsbe in parallel and form the raceway groove unit in parallel that distributes, a plurality of described raceway grooves distribute unit in parallel mutually connect after one end and the dead resistance R that connects _dbe in series, the other end and the dead resistance R that connects _sbe in series, described series connection dead resistance R _dwith series connection stray inductance L _dbe in series, described series connection dead resistance R _swith series connection stray inductance L _sbe in series.

Further, described step 20 is by V _gs1and V _gs2time two groups of S parameter transformations obtain two groups of Z parameters and be respectively with again according to formula

$n=\frac{\mathrm{Re}\left(Z_{11}^1\right)-\mathrm{Re}\left(Z_{11}^2\right)}{\mathrm{kT}/({\mathrm{qI}}_{\mathrm{gs}1}-q{I}_{\mathrm{gs}2})}$ With $R_{\mathrm{gs}}=\frac{\mathrm{nkT}}{{\mathrm{qI}}_{\mathrm{gs}}}$

Calculate n and R _gs, R _gsfor grid end Schottky resistance, and can obtain following equation according to transmission line equivalent equation:

$Z_{11}=R_s+R_g+\frac{Z_0}{\tanh \left(\mathrm{\γL}\right)}+\mathrm{j\ω}(L_s+L_g)---\left(4\right)$

$Z_{12}=Z_{21}=R_s+\frac{Z_0(\cosh \left(\mathrm{\γL}\right)-1)}{\sinh \left(\mathrm{\γL}\right)}+\mathrm{j\ω}{L}_s---\left(5\right)$

$Z_{22}=R_s=R_d+\frac{{2Z}_0(\cosh \left(\mathrm{\γL}\right)-1)}{\sinh \left(\mathrm{\γL}\right)}+\mathrm{j\ω}(L_s+L_d)---\left(6\right)$

Δ R wherein _ch=R _ch* Δ x, Δ C _ds=C _ds* Δ x, Δ R _gs=R _gs* Δ x, Δ C _g=C _g* Δ x, Δ x is the infinitely small length along grid length direction.

Wherein: Z ₀be characteristic impedance, γ L is transmission and along the product of the length of grid length direction,

$Z_0=\sqrt{\frac{R_{\mathrm{ch}}//C_{\mathrm{ds}}}{1/R_{\mathrm{gs}}+\mathrm{j\ω}{C}_g}}$

$\mathrm{\γL}=\sqrt{(R_{\mathrm{ch}}//C_{\mathrm{ds}})(1/R_{\mathrm{gs}}+\mathrm{j\ω}{C}_g)}$

Due to | (γ L) ²| < < 1, ω R _chc _ds< < 1, ω R _gsc _g< < 1, by obtaining the Z parametric form of formula (7)～(9) after abbreviation,

Z ₁₁＝R _s+R _g+R _gs+α _gR _ch+jω(L _s+L _g) (7)

Z ₁₂＝Z ₂₁＝R _s+αR _ch+jωL _s (8)

Z ₂₂＝R _s+R _d+2αR _ch+jω(L _s+L _d) (9)

Wherein due to Re (Z ₁₁) with

$R_{\mathrm{gs}}=\frac{\mathrm{nkT}}{q{I}_{\mathrm{gs}}}$

Proportional relation, so by measuring curve, the intercept of linear fit is exactly R _s+ R _g+ α _gr _chand, simultaneously due to v wherein _thfor threshold voltage, measure curve, the matching intercept that low leakage is pressed is R _d+ R _s, in conjunction with the formula of (7)～(9) above, just can calculate corresponding resistance value so again, then by real part and imaginary part, calculate respectively series connection dead resistance and the stray inductance of connecting:

R _g＝real(Z ₁₁)-real(Z ₁₂)+R _ch/6，R _d＝real(Z ₂₂)-real(Z ₁₂)-R _ch/2，

R _s＝real(Z ₁₂)-R _ch/2，L _g＝imag(Z ₁₁-Z ₁₂)/ω，

L _d＝imag(Z ₂₂-Z ₁₂)/ω，L _s＝imag(Z ₁₂)/ω，

α wherein _gbe generally 1/3 and 1/2 with α.

Further, described step 30 calculates the inside intrinsic parameters value gate capacitance C under certain bias state _gs, C _gd, mutual conductance g _mand delay factor τ _m, source leakage conductance g _dsand drain terminal delay factor τ _ds, drain-source capacitor C _dswith grid source channel resistance R _iprocess comprise: the intrinsic S parameter transformation of inner parameter is being obtained to Y parameter, and according to formula (10)～(13)

$Y_{11}=\frac{R_i{C}_{\mathrm{gs}}^2{\mathrm{\&omega;}}^2}{D}+\mathrm{j\&omega;}(\frac{C_{\mathrm{gs}}}{D}+C_{\mathrm{gd}})---\left(10\right)$

Y ₁₂＝-jωC _gd (11)

$Y_{21}=\frac{g_m{e}^{-\mathrm{j\&omega;}{\mathrm{\&tau;}}_m}}{1+\mathrm{j\&omega;}{R}_i{C}_{\mathrm{gs}}}-\mathrm{j\&omega;}{C}_{\mathrm{gd}}---\left(12\right)$

$Y_{22}=g_{\mathrm{ds}}{e}^{-\mathrm{j\&omega;}{\mathrm{\&tau;}}_{\mathrm{ds}}}+\mathrm{j\&omega;}(C_{\mathrm{gd}}+C_{\mathrm{ds}})---\left(13\right)$

Wherein, $D=1+{\mathrm{\&omega;}}^2{C}_{\mathrm{gs}}^2{R}_i^2,$

And adopting real part and imaginary part to equate respectively, the numerical value that calculates inner intrinsic parameters is respectively

g _ds＝real(Y ₂₂)， ${\mathrm{\&tau;}}_{\mathrm{ds}}=\frac{1}{\mathrm{\&omega;}}\sqrt{(2-2*\mathrm{real}\left(Y_{22}\right)/g_{\mathrm{ds}})},$

$C_{\mathrm{gs}}=\frac{(1+D^2)}{\mathrm{\&omega;}}*(\mathrm{imag}\left(Y_{11}\right)+\mathrm{imag}\left(Y_{12}\right)),R_i=\frac{D}{(1+D^2)*(\mathrm{imag}\left(Y_{11}\right)+\mathrm{imag}\left(Y_{12}\right))},$

$C_{\mathrm{gd}}=-\frac{\mathrm{imag}\left(Y_{12}\right)}{\mathrm{\&omega;}},C_{\mathrm{ds}}=\frac{\mathrm{imag}\left(Y_{22}\right)+\mathrm{imag}\left(Y_{21}\right)}{\mathrm{\&omega;}}+g_{\mathrm{ds}}*{\mathrm{\&tau;}}_{\mathrm{ds}},$

$g_m=\sqrt{(1+D^2)*(\mathrm{real}{\left(Y_{21}\right)}^2+{(\mathrm{imag}\left(Y_{21}\right)-\mathrm{imag}\left(Y_{12}\right))}^2)},$

${\mathrm{\&tau;}}_m=-\frac{1}{\mathrm{\&omega;}}*\arctan \left(\frac{D*\mathrm{real}\left(Y_{21}\right)+\mathrm{imag}\left(Y_{21}\right)-\mathrm{imag}\left(Y_{12}\right)}{\mathrm{real}\left(Y_{21}\right)-D*(\mathrm{imag}\left(Y_{21}\right)-\mathrm{imag}\left(Y_{12}\right))}\right).$

The invention has the beneficial effects as follows: the parameter extracting method of AlGaN/GaN HEMT small-signal model of the present invention can obtain the design parameter corresponding with device topological structure, so just the physical mechanism of device with together with parameter association in concrete technology step, be convenient to analyze physical process and find the problem in device fabrication processes, for different results, also can contrast, for improving processing step and upgrading device architecture, have very much reference value like this; After small-signal parameter extracts, just can set up the small signal equivalent model of device, for the circuit design under small-signal applications, can emulation obtain gain and the S parameter under certain bias state, simultaneously also for the foundation of large-signal model lays the first stone, so the accurate extracting method of small-signal parameter gets a good eye value.

Accompanying drawing explanation

Fig. 1 is the AlGaN/GaN HEMT device architecture schematic diagram adopting in the parameter extracting method of embodiment of the present invention AlGaN/GaN HEMT small-signal model;

Fig. 2 is the parameter equivalent circuit diagram of Fig. 1;

Fig. 3 is the equivalent circuit diagram that the open circuit that extracts peripheral stray capacitance parameter in the parameter extracting method of embodiment of the present invention AlGaN/GaN HEMT small-signal model removes embedding figure;

Fig. 4 is the equivalent circuit diagram of device channel distribution parameter in the parameter extracting method of embodiment of the present invention AlGaN/GaN HEMT small-signal model;

Fig. 5 is the high frequency characteristics figure of the device of institute's extracting parameter in the parameter extracting method of embodiment of the present invention AlGaN/GaN HEMT small-signal model;

Fig. 6 introduces grid end Schottky resistance R in the parameter extracting method of embodiment of the present invention AlGaN/GaN HEMT small-signal model _gsafter, the small-signal equivalent circuit parameter of extracting is to S ₁₁improvement situation contrast schematic diagram;

Fig. 7 introduces the delay factor τ of source leakage conductance in the parameter extracting method of embodiment of the present invention AlGaN/GaN HEMT small-signal model _dsafter, the small-signal equivalent circuit parameter of extracting is to S ₂₂improvement situation contrast schematic diagram.

Embodiment

Below in conjunction with accompanying drawing, principle of the present invention and feature are described, example, only for explaining the present invention, is not intended to limit scope of the present invention.

Fig. 1 is the AlGaN/GaN HEMT device architecture schematic diagram adopting in the parameter extracting method of embodiment of the present invention AlGaN/GaN HEMT small-signal model, after concrete example be exactly to adopting this device architecture to carry out the explanation that parameter extracting method carries out.The extraction of small-signal parameter is requisite link in the modeling of FET semiconductor devices, the accurate extraction of peripheral parasitic parameter can have influence on the accuracy of internal nonlinearity parameter, the extraction of small-signal model is the basis that large-signal model is set up, only guaranteed all small-signal parameter values are accurately reasonable, can set up more accurately large-signal model.

Fig. 2 is the equivalent circuit diagram of Fig. 1.As shown in Figure 2, this equivalent circuit diagram comprises peripheral stray capacitance C _pg, C _pd, C _pgd, series connection dead resistance R _g, R _d, R _s, series connection stray inductance L _g, L _d, L _s, gate capacitance C _gs, C _gd, mutual conductance g _mand delay factor τ _m, source leakage conductance g _dsand drain terminal delay factor τ _ds, drain-source capacitor C _dswith grid source channel resistance R _i, Vi is capacitor C _gsthe voltage at two ends, Vd is capacitor C _dsthe voltage at two ends, the method for parameter extraction is also how above-mentioned parameter in this equivalent circuit diagram is extracted to the explanation of carrying out here.

Fig. 3 is the equivalent circuit diagram that in the parameter extracting method of embodiment of the present invention AlGaN/GaN HEMT small-signal model, open circuit removes embedding figure, has three peripheral stray capacitance parameters C _pg, C _pd, C _pgd.

Fig. 4 is the equivalent circuit diagram of device channel distribution parameter in the parameter extracting method of embodiment of the present invention AlGaN/GaN HEMT small-signal model, and as shown in Figure 4, grid end distributed resistance and distributed capacitance are respectively Δ R _gswith Δ C _g, raceway groove distributed resistance and distributed capacitance are respectively Δ R _chwith Δ C _ds, by transmission line equivalent equation abbreviation, can obtain the solving equation of this equivalent electrical circuit, then calculate the numerical value of series connection dead resistance and series connection stray inductance.

Fig. 5 is the high frequency characteristics figure of the device of institute's extracting parameter in the parameter extracting method of embodiment of the present invention AlGaN/GaN HEMT small-signal model.In order to verify the accuracy of the lower small-signal parameter that extracts of fixed bias state, need the effect of measurement of comparison S parameter and models fitting S parameter, and by the formula of reflection device physical significance

$f_T=\frac{g_m}{2\mathrm{\&pi;}(C_{\mathrm{gs}}+C_{\mathrm{gd}})[1+(R_s+R_d)g_{\mathrm{ds}}]+C_{\mathrm{gd}}{g}_m(R_s+R_d)}---\left(14\right)$

And

$f_{\max }=\frac{f_T}{2\sqrt{((R_g+R_i+R_s)g_{\mathrm{ds}}+2\mathrm{\&pi;}{f}_T{C}_{\mathrm{gd}}{R}_g)}}---\left(15\right)$

The high frequency characteristics of the device of prediction institute extracting parameter, whether accurately the high frequency characteristics contrast with actual measurement, can be used as and judge institute's extracting parameter standard, as can be seen from Figure 5 measured this device cutoff frequency f _tfor 36GHz, maximum oscillation frequency f _maxfor 58GHz, adopt the parameter of extracting in table 1 below, the f predicting with formula (14) and (15) _tfor 34.9GHz, f _maxfor 56.4GHz, the small-signal equivalent circuit parameter that adopts as can be seen here the method to extract not only has physical significance, and the S parameter of matching is effective, and can well predict the high frequency characteristics of device, illustrates that extracted parameter is very accurate.

Fig. 6 is by introducing grid end Schottky resistance R in the parameter extracting method of embodiment of the present invention AlGaN/GaN HEMT small-signal model _gsafterwards to S in small signal S-parameters ₁₁improvement situation contrast schematic diagram.As shown in Figure 6, can find out if there is no R _gs, gate resistance R _gcan be bigger than normal, S ₁₁under high frequency, can produce skew, affect the characteristic under device high frequency, introduce R _gsafter, to R _gextraction more accurate, will improve the S under high frequency like this ₁₁curve, in figure, ' o ' measures S parameter result, and '-' is emulation S parameter result, can find out that right figure has clear improvement with respect to left figure.

Fig. 7 is by the drain terminal delay factor τ of introducing source leakage conductance in the parameter extracting method of embodiment of the present invention AlGaN/GaN HEMT small-signal model _dsafterwards to S in small signal S-parameters ₂₂improvement situation contrast schematic diagram.As shown in Figure 7, do not introduce τ _dstime, S under high frequency ₂₂can be greatly affected, and when extracting inner parameter, C _dsparameter often there will be negative value.Because the time constant of grid lower area not only comprises mutual conductance g _mdelay factor τ _m, also have it by depletion region caused drain terminal delay factor τ very large between grid leak _ds, τ _dsintroducing improve drain terminal signal along with the delay of grid end signal, simultaneously the transmission of signal has also been described more accurately along with the variation of bias voltage and frequency.In figure, ' o ' measures S parameter result, and '-' is emulation S parameter result, can find out that right figure has clear improvement with respect to left figure.

Table 1 is all small-signal parameter values of institute's extraction device in the parameter extracting method of embodiment of the present invention AlGaN/GaN HEMT small-signal model.This table 1 is the parameter that the device architecture for Fig. 1 extracts, this device be grid long be 0.3um, the parameter value that the GaN HEMT device that grid width is 4 * 100um extracts.

Table 1

C pg＝9.96fF	C pg＝13.04fF	C pgd＝2.34fF	R g＝4.08Ohm
				R d＝0.5Ohm	R s＝4.0Ohm	R gs＝4.5Ohm	L g＝0.02pH
L d＝0.04pH	L s＝0.001pH	C gs＝0.197pF	C gd＝0.074pF
				C ds＝0.025pF	g m＝65.06mS	τ m＝1.3ps	R i＝1.5Ohm
g ds＝3.08mS	τ ds＝5.62ps

It is the situation of negative value that the extraction of traditional small-signal model parameter often there will be extracting parameter, and corresponding S parameter fitting is in bad order.Structure and characteristics for AlGaN/GaN HEMT device, because small-signal parameter is to link together with the physical topological structure of device, so just contact tightr with operational characteristic and physical characteristics, so need the parameter of extracting to have physical significance, this also just proposes specific criteria to the method for extracting parameter, when weighing the accuracy of small-signal parameter, first to guarantee that it is consistent with the physical parameter meaning of institute extraction device, and S parameter fitting is effective, simultaneously can Accurate Prediction high frequency characteristic data f _tand f _max, therefore to the research of the extracting method of small-signal parameter highly significant.

The parameter extracting method of AlGaN/GaN HEMT small-signal model of the present invention is mainly to adopt identically with the device periphery structure of institute extracting parameter, does not have the open circuit of active area part to go embedding figure to carry out the peripheral stray capacitance of calculating device; Introduce parasitic Schottky gate resistance R _gs, adopt the test under specified conditions to calculate this resistance, the extraction of make like this to connect dead resistance and inductance is more reasonable, also for obtaining intrinsic parameters accurately, lays the groundwork; In the leakage conductance of source, introduce delay factor τ _ds, can improve C _dsextraction, it is more reasonable to make in to the description of the equivalent electrical circuit of device.Checking by experiment, whole parameter extraction process is for reducing negative value and the matching, the especially S that improve S parameter ₁₁and S ₂₂the improvement of fitting effect especially obvious.

The accurate extraction of small-signal parameter is for instructing processing step, characterization processes accuracy, improve device architecture, the impact of research design parameter on device high frequency characteristics, monitoring and contrast and experiment have very important significance, also for the foundation of device large-signal model lays the first stone, there is good Research Significance and practical value simultaneously.

The foregoing is only preferred embodiment of the present invention, in order to limit the present invention, within the spirit and principles in the present invention not all, any modification of doing, be equal to replacement, improvement etc., within all should being included in protection scope of the present invention.

Claims (5)

1. a parameter extracting method for AlGaN/GaN HEMT small-signal model, is characterized in that, described parameter extracting method comprises:

Step 10: measure peripheral open circuit and remove the scattering parameter S of embedding circuit, and its conversion is obtained to admittance parameter Y, thereby calculate peripheral stray capacitance C _pg, C _pdand C _pgdnumerical value, described peripheral open circuit goes embedding circuit to comprise peripheral stray capacitance C _pg, C _pdand C _pgd, described peripheral stray capacitance C _pgdseries connection C _pgand C _pdbetween;

Step 20: at V _gs>0, V _dsunder the bias state of=0V, select the gate voltage value of two groups of AlGaN/GaN HEMT devices to be respectively V _gs1and V _gs2, test obtain two groups respectively with two groups of gate voltage value current value I corresponding and that be less than 10mA _gs1and I _gs2, then measure gate voltage value and be respectively V _gs1and V _gs2time S parameter, and its conversion is obtained to impedance parameter Z, then calculates the numerical value of series connection dead resistance and series connection stray inductance; Described step 20 is by V _gs1and V _gs2time two groups of S parameter transformations obtain two groups of Z parameters and be respectively with again according to formula

with

Calculate n and R _gs, R _gsfor grid end Schottky resistance, and can obtain following equation according to transmission line equivalent equation:

△ Rch=Rch * △ x wherein, △ Cds=Cds * △ x, △ Rgs=Rgs * △ x, △ Cg=Cg * △ x, △ x is the infinitely small length along grid length direction;

Wherein: Z ₀be characteristic impedance, γ L is transmission and along the product of the length of grid length direction,

You Yu ∣ (γ L) ²∣ <<1, ω RchCds<<1, ω RgsCg<<1, by obtaining the Z parametric form of formula (7)～(9) after abbreviation,

Z ₁₁=R _s+R _g+R _gs+α _gR _ch+jω(L _s+L _g) (7)

Z ₁₂=Z ₂₁=R _s+αR _ch+jωL _s (8)

Z ₂₂=R _s+R _d+2αR _ch+jω(L _s+L _d) (9)

Wherein due to Re (Z ₁₁) with

Proportional relation, so by measuring curve, the intercept of linear fit is exactly R _s+ R _g+ α _gr _chand, simultaneously due to v wherein _thfor threshold voltage, measure curve, the matching intercept that low leakage is pressed is R _d+ R _s, in conjunction with the formula of (7)～(9) above, just can calculate corresponding resistance value so again, then by real part and imaginary part, calculate respectively series connection dead resistance and the stray inductance of connecting:

R _g=real(Z ₁₁)-real(Z ₁₂)+R _ch/6，R _d=real(Z ₂₂)-real(Z ₁₂)-R _ch/2，

R _s=real(Z ₁₂)-R _ch/2，L _g=imag(Z ₁₁-Z ₁₂)/ω，

L _d=imag(Z ₂₂-Z ₁₂)/ω，L _s=imag(Z ₁₂)/ω，

α wherein _gbe generally 1/3 and 1/2 with α;

Step 30: measure the S parameter of AlGaN/GaN HEMT device under bias state, remove the peripheral stray capacitance C calculating in step 10 _pg, C _pdand C _pgdthe series connection dead resistance R obtaining with step 20 _g, R _d, R _swith series connection stray inductance L _g, L _d, L _s, obtain the intrinsic S parameter of inner parameter, and its conversion obtained to Y parameter, then calculate the inside intrinsic parameters gate capacitance C under bias state _gs, C _gd, mutual conductance g _mand delay factor τ _m, source leakage conductance g _dsand drain terminal delay factor τ _ds, drain-source capacitor C _dswith grid source channel resistance R _inumerical value.

2. the parameter extracting method of AlGaN/GaN HEMT small-signal model according to claim 1, is characterized in that, described step 10 calculates peripheral stray capacitance C _pg, C _pdand C _pgdthe process of numerical value comprise: S parameter transformation is obtained to Y parameter, and according to formula (1)～(3)

Im(Y ₁₁)=ω(C _pg+C _pgd) (1)

Im(Y ₁₂)=Im(Y ₂₁)=-ωC _pgd (2)

Im(Y ₂₂)=ω(C _pd+C _pgd) (3)

Calculate peripheral stray capacitance C _pg, C _pdand C _pgdnumerical value be respectively

3. the parameter extracting method of AlGaN/GaN HEMT small-signal model according to claim 1, it is characterized in that, the gate voltage value of two groups of AlGaN/GaN HEMT that select in described step 20 is all greater than the Schottky voltage of AlGaN/GaN HEMT, and current value corresponding to gate voltage value of two groups of AlGaN/GaN HEMT is all less than 10mA simultaneously.

4. the parameter extracting method of AlGaN/GaN HEMT small-signal model according to claim 3, is characterized in that, described step 20 is at V _gs>0, V _dsunder the bias state of=0V, the equivalent electrical circuit of AlGaN/GaNHEMT device comprises series connection dead resistance R _g, R _dand R _s, series connection stray inductance L _g, L _dand L _s, a plurality of grid end distributed resistance △ R _gs, a plurality of grid end distributed capacitance △ C _g, a plurality of raceway groove distributed resistance △ R _chwith a plurality of raceway groove distributed capacitance △ C _ds, wherein, grid end distributed resistance △ R _gswith grid end distributed capacitance △ C _gbe in parallel and form the grid end unit in parallel that distributes, a plurality of described grid ends distribute unit in parallel parallel with one another after with the dead resistance R that connects _gbe in series, described series connection dead resistance R _gwith series connection stray inductance L _gbe in series, raceway groove distributed resistance △ R _chwith raceway groove distributed capacitance △ C _dsbe in parallel and form the raceway groove unit in parallel that distributes, a plurality of described raceway grooves distribute unit in parallel mutually connect after one end and the dead resistance R that connects _dbe in series, the other end and the dead resistance R that connects _sbe in series, described series connection dead resistance R _dwith series connection stray inductance L _dbe in series, described series connection dead resistance R _swith series connection stray inductance L _sbe in series.

5. the parameter extracting method of AlGaN/GaN HEMT small-signal model according to claim 1, is characterized in that, described step 30 calculates the inside intrinsic parameters value gate capacitance C under bias state _gs, C _gd, mutual conductance g _mand delay factor τ _m, source leakage conductance g _dsand drain terminal delay factor τ _ds, drain-source capacitor C _dswith grid source channel resistance R _iprocess comprise: the intrinsic S parameter transformation of inner parameter is being obtained to Y parameter, and according to formula (10)～(13)

Y ₁₂=-jωC _gd (11)

Wherein,

And adopting real part and imaginary part to equate respectively, the numerical value that calculates inner intrinsic parameters is respectively

g _ds=real(Y ₂₂)，