CN1114227C - Method and system for analyzing parameters of semiconductor - Google Patents

Abstract

The present invention relates to a method and a system for analyzing operators of parameter proportion differential values of semiconductor devices. A semiconductor parameter test instrument is used for measuring complete semiconductor device I-V output characteristics; then, the proportion differential value processing of a software system on the I-V characteristics is analyzed through the proportion differential values to obtain corresponding proportion differential value I-V function characteristics and semiconductor parameters. Compared with the traditional fitting method or extrapolation method, the present invention has the advantages of high accuracy, short test program and obvious improvement on work efficiency, and the present invention can be used in the technical field of semiconductor parameter information processing.

Description

The analyzing parameters of semiconductor system

Technical field:

Technical field is the semiconductor parameter field of information processing under this patent.Relate generally to a kind of semiconductor device parametric analysis system.

Background technology:

Major parameter about metal monooxide semiconductor field-effect transistor: the main existing detection technique of channel carrier mobility and threshold voltage:

(1). electric current linear extrapolation method ^[1]: under the less situation of drain voltage (≤100mv), obtaining the linear relationship of grid voltage and leakage current, the intercept of its linear extrapolation is a threshold voltage, and slope is relevant carrier mobility.(see [1] D.K.Schroder, " Semiconductor Material and DeviccCharacterization ", Wiley-Inter.science, chap.4，New?York，1990)

(2) electric current root Extrapolation method: utilize the saturation characteristic of MOSFET, obtain the linear relationship of gate voltage and current squaring root, the intercept of its linear extrapolation is a saturation threshold voltage, and slope is relevant mobility.

Above-mentioned two kinds of methods in fact all do not satisfy the ideal linearity requirement, in the high-end variation owing to mobility of gate voltage, and in the existence of gate voltage low side owing to the subthreshold region electric current, all can lose linearity, thereby only have limited linearity range.Under the situation that the device size of very lagre scale integrated circuit (VLSIC) constantly diminishes, this linearity range becomes shorter and shorter, this be two parameters determine to bring uncertain factor.

Summary of the invention:

Analyzing parameters of semiconductor of the present invention system comprises the semiconductor parametric tester device, computer, testboard, computer and tester interface card, the analyzing parameters of semiconductor software systems, the semiconductor parametric tester device is measured complete semiconductor device I-V output characteristic; The analyzing parameters of semiconductor software systems are carried out the proportional difference processing to the I-V characteristic that records and are drawn proportional difference I-V function characteristic and semiconductor parameter.

Above-mentioned I-V output characteristic comprises the triode service area of semiconductor device, and the asymptotic or accurate asymptotic I-V characteristic of the semiconductor device that obtains of fractional saturation or quasi saturation district.

Proportional difference constant K value of the present invention is between 1.01-10.

Above-mentioned semiconductor software analysis system comprises with counterdie fast: Subscriber Interface Module SIM; Test module; Analysis module; Data management module; Data demonstration/print module.

Basic principle of the present invention is as follows:

1. the basic thought of proportional difference operator technology

Proportional difference Δ with a kind of function f (x) _PF (x) is defined as:

Δ _Pf(x)＝f(kx)-f(x) (1)

K is one and is called the proportional difference constant greater than 1 positive number in the formula, and Δ _PBe called proportional difference operator.

2. asymptotic function proportional difference spectral theorem (seeing [2] and [3])

If a kind of function f (x), and in the interval (0, be continuously ∞), the function of increasing or decreasing that can be little, and f (o)=A is arranged, and f (∞)=B, wherein A and B are two constants.So, and in the interval (0, ∞) must there be a bit (x _P), satisfy $\frac{d{\mathrm{\Δ}}_{P}f\left(x\right)}{\mathrm{dx}}{|}_{x=x_P}=0---\left(2\right)$

This theorem (seeing [2] and [3]) can be by the Rolle theorem proving.

So, the Δ of asymptotic function _PF (x) value is in that (0, ∞) there is extreme value in the interval, i.e. Δ _PF (x) is a kind of spectral function.So the spectrum peak heights is relevant with the asymptotic value f (∞) of f (x), and x _PRelevant with the characteristic parameter of f (x) function, thus two important parameters of f (x) function obtained, finished the quantitative analysis of f (x) function.

The difference of proportional difference and equivalent difference and the characteristics on technical application thereof

1. to get the ratio of adjacent two independents variable be constant to proportional difference, and equivalent specification requirement adjacent two

The difference of individual independent variable is a constant, and requires this constant to measure less than certain, to obtain outstanding variable quantity, presses

The effect of independent variable contracts.And in the proportional difference technology, then do not have this type of strong restrictions.

2. the selection of the independent variable in the proportional difference technology is freely, does not promptly have the localization restriction, and calculates at equivalence

In, be conditional to independent variable, it is two mean values between the difference.

Two above characteristics bring many conveniences for the proportional difference technology.

The present invention measures complete semiconductor device I-V output characteristic by the semiconductor device parameter tester, and with the proportional difference operator processor system above-mentioned I-V characteristic is carried out proportional difference and handle, obtain the corresponding proportional difference I-V output spectra characteristic of new device property----, and directly determine the semiconductor device parameter with peak position and peak heights.Compare with traditional fitting process or extrapolation, improved precision, shortened routine analyzer, improved work efficiency significantly.Can be applicable to each yardstick semiconductor device parameter information process field.

Description of drawings

Fig. 1 MOS product body pipe typical case drain characteristics (a), conventional difference characteristic (b) and proportional difference characteristic (c) thereof

The typical case of Fig. 2 P-N junction diode is I-V characteristic, conventional difference characteristic and proportional difference characteristic oppositely

Fig. 3 semiconductor device parameter proportional difference operator analytical technology system architecture diagram

Fig. 4 software system structure block diagram

Fig. 5 analysis module block diagram

The MOS transistor proportional difference spectral property that Fig. 6 proportional difference technology draws

Embodiment:

1 determines the proportional difference operator method of MOS transistor parameter

The voltage-current characteristic of MOS transistor can be expressed as (seeing M.S.Sze, " Phusics of SemiconductorDevices ", 2 ^Nd, Ed.Wiley-Iner.science, New York, 1981, Chap.8) $I=\frac{Z}{L}{\mathrm{\μ}}_n{C}_i\{(V_G-2{\mathrm{\φ}}_B-V_{\mathrm{FB}}-\frac{V_D}{2})V_D-\frac{2}{3}\mathrm{\γ}[{(V_D+{2\mathrm{\φ}}_B)}^{3/2}-{\left({2\mathrm{\φ}}_B\right)}^{3/2}\left]\right\}---\left(3\right)$

In the formula, Z/L is the breadth length ratio of transistor, C _iBe SiO ₂Electric capacity.μ _nBe electron mobility, φ _BBe semi-conducting material Fermi potential, V _FBBe flat band voltage, γ is the bulk effect factor.

By (3) formula as can be seen, at V _GUnder the given situation, electric current I is at first with drain terminal voltage V _DLinear increase (linear zone) then, is tending towards saturation value (saturation region).Figure one has provided MOS transistor drain characteristics (I _D～V _D), conventional difference (Δ I _D～V _D) and proportional difference characteristic (Δ _PI _D～V _D) schematic diagram, the drain terminal voltage (V when dotted line represents that leakage current reaches maximum _Dsat) track.

By figure one as seen, equation (3) can be considered and satisfies asymptotic approximate function, so can ask its proportional difference to be with proportional difference spectral function theorem ${\mathrm{\Δ}}_{P}I=\frac{Z}{L}{\mathrm{\μ}}_n{C}_i\{(V_G-V_{\mathrm{FB}}-2{\mathrm{\φ}}_B)(K-1)V_D-\frac{1}{2}(K^2-1)V_D^2-\frac{2}{3}\mathrm{\γ}---\left(4\right)$ [(KV _D+2φ _B) ^3/2-(V _D+2φ _B) ^3/2]}

It is easy to show that, work as V _DChange to V _DPThe time, Δ _PPeak value appears in I, promptly $\frac{{\∂\mathrm{\Δ}}_{P}I}{{\∂V}_D}{|}_{V_D-V_{\mathrm{DP}}}=0---\left(5\right)$

Can try to achieve

(K+1)V _DP＝V _Dsat (6)

On the other hand

V _G-V _Dsat＝V _Dsat (7)

And $V_G-V_{\mathrm{FB}}-{2\mathrm{\φ}}_B=(K+1)V_{\mathrm{DP}}+\mathrm{\γ}\sqrt{(K+1)V_{\mathrm{DP}}+{2\mathrm{\φ}}_B}---\left(8\right)$

Work as V _DP→ 0 o'clock, (8) formula was reduced to $V_G(V_{\mathrm{DP}}=0)=V_{T0}\left({\mathrm{\φ}}_B\right)=V_{\mathrm{FB}}+2{\mathrm{\φ}}_B+\mathrm{\γ}\sqrt{2{\mathrm{\φ}}_B}---\left(9\right)$ So,, can determine saturation threshold voltage V at last by (7), (9) two formulas _TsatAnd classical threshold voltage V _TOValue.

Mobility can be obtained by following formula: $\mathrm{\μ}=\frac{2{\mathrm{\Δ}}_{P}I\left(V_{\mathrm{DP}}\right)}{\left(\frac{Z}{L}\right)C_i(k^2-1)V_{\mathrm{DP}}^2}---\left(10\right)$

In the formula, Z/L, C _iBe the known device size constants, in case Δ _PI (V _DP) and V _DPDetermine that μ is also just obtained by (10) formula.

Thus can

(i) obtain new difference characteristic----proportional difference characteristic, it is different with conventional difference characteristic, its tool

The spectrum peak character is arranged, and this specific character can be used as a kind of new device performance index and judges the basic of device

Characteristic, μ is big for the high expression of peak value device, and mutual conductance is big; Peak position is big, and the expression threshold voltage is big.

The (ii) simplification of processing data information

Only by an I _D～V _DGeneral measure, and Δ _PI _D～V _DCharacteristic is handled just can obtain the result, and

Need not change mode of operation as other method, make little V _DRestriction.

The (iii) measurement respectively of threshold voltage and mobility: gate voltage (Vg) is to the influence of mobility, no

Influence determining of threshold voltage.

(iv) this technology has provided a kind of definite saturation region threshold voltage V _DsatMethod, particularly ditch is being arranged

The road modulation, V _DsatUnder can't accurately fixed situation, outstanding strong point especially.

(v) eliminated the influence of subthreshold electric current.Because the method is to advance near under the perfect condition at device property

Row, formula (4) can fully accurately be described its fundamental characteristics, and is irrelevant with the subthreshold region electric current.

2. determine the proportional difference operator technology of PN junction diode characteristic parameter

The reverse current characteristics of PN junction can be described (seeing [4]) with following formula

I＝I _S(1-e ^-V/Vt) (11)

I _SBe reverse saturation current value, V _t=KT/q is called thermoelectric potential, and K is a Boltzmann constant, and T is the ambient temperature of device work, and q is an electronic charge.

Be not difficult to find out that (11) formula also is a kind of typical asymptotic function, when V=0, I=0; And when V → ∞, I=I _S

So, can determine the corresponding devices parameter I easily with the proportional difference operator method _SWith the Vt value.

With proportional difference operator (11) formula is carried out computing, its result is

Δ _PI＝I _S(e ^-v/vt-e ^-kv/vt) (12)

Ask extreme value $\frac{{\∂\mathrm{\Δ}}_{P}I}{\∂V}{|}_{V=V_m}=0---\left(13\right)$ Can get V _t=(k-1) V _m/ lnK (14) $I_S=K^{\frac{K}{K-1}{\mathrm{\Δ}}_{P}I\left(V_m\right)}/(K-1)---\left(15\right)$

Diode reverse I-V characteristic, conventional difference characteristic Δ I-V and proportional difference characteristic Δ _PThe I-V curve is respectively shown in Fig. 2 (a) and (b), (c).

Thus can

(i) obtained new the reverse characteristic---proportional difference characteristic of PN junction diode, it and conventional difference characteristic are relatively, and be obviously different.A kind of new performance index that its spectrum peak can be used as the PN junction diode are utilized.For example, the high expression of peak value leakage current is big, and the big expression PN junction of peak position is undesirable etc.

(ii). it is characteristics of the present invention that data processing is simplified

To determine that in conventional method these two parameters will carry out match repeatedly and just can obtain satisfied result.And the application Δ _PThe spectrum peak character that the characteristic of I-V provides is simplified handling procedure greatly.

(iii). the place of peak value appears in the present invention, is at V as long as note _tThe magnitude of=KT/q=26mv (room temperature), and be far smaller than the voltage of launching in the High-Field (greater than 1v), just can guarantee determining of device parameters.Thereby after having overcome reverse voltage and increasing, because the influence of internal field emission, saturated phenomenon does not take place in electric current, for the difficulty of definite generation of device parameters.

(iv). owing to be under low pressure promptly to have finished determining of device parameters, the correction that series resistance under the big electric current and thermal effect cause can greatly be improved.

(v). present technique has realized the PN junction diode under application conditions, to the temperature monitoring of environment.Vt is the sign amount of its ambient temperature, and this is particularly important in the alternating temperature experiment.

In the technical field of measurement and test of semiconductor parameter, the HP4140 series semiconductor device parameters analyzer that Hewlett-Packard Corporation produces almost forms the monopolization situation in the international market, is a kind of generally acknowledged high-tech product.But the function of this product still is based on existing principle, method.Though Hewlett-Packard's instrument upgrades every year, bring in constant renewal in, still, we do not appear in this series products as yet the proportional difference technology of research, our technology of proportion of utilization differential analysis becomes semiconductor device parameter proportional difference analytical technology system with the HP instrument combination, obtained the checking that this technology is used.

Analyzing parameters of semiconductor of the present invention system is by forming with the lower part: one in the above ibm compatible personal computer machine of 486/66/8MB, software systems, HP4145B transistor parameter analyzer or one of BC2931A transistor constant measuring instrument, supporting testing cassete or sample stage, Fig. 3 is the structure chart of this system.

Software system structure block diagram of the present invention such as Fig. 4.According to the software system structure block diagram, we adopt Visual C++5.0 to realize under Windows95/NT.Adopting the Doc/View mode in the master-plan, is that core is managed all data with document (Document), comes display result with looking (View), receives user's input by user interface.Based on above consideration, whole procedure can probably be divided into following module:

Subscriber Interface Module SIM;

Test module;

Analysis module;

Data management module, i.e. document module;

Data demonstration/print module

1, Subscriber Interface Module SIM

Subscriber Interface Module SIM mainly is to realize human-computer interaction function, the input of process user.Interface Design adopts up-to-date look ﹠ feel under the Windows, directly perceived, easy operating.

2, test module

For test module, because we consider that different users may have different testers, so this software has proposed a kind of like this conception to part of detecting: an instrument test control interface is set in program, define a unified user interface simultaneously, the user just can monitor and data acquisition with this software as long as according to this standard the instrument control procedure of oneself is made dynamic base.The result of test is managed by document module.

3, analysis module

Analysis module is the nucleus module of this software, is the main modular of carrying out data analysis.In this module, used a large amount of scientific and technological counting subroutines and experimental data has been handled in conjunction with our analysis of spectrum skill.The theoretical foundation of deal with data is the basic principle of proportional difference spectrum.

This analysis module is mainly handled the experimental data of I-V characteristic, the structured flowchart of this module such as Fig. 5.

4, data management module, i.e. document module

Data management module mainly is responsible for the management of all experiment conditions, sample parameters, analysis condition, experimental data, analyst result and intermediate data and data display parameters, simultaneously the analysis remarks of being done in the also administrative analysis process.This module adopts is that the Cdocument class of MFC realizes as base class.Used the array template of MFC in storage, all data all are stored in the file with binary mode.Avoided a shortcoming that a plurality of files of experiment are not easy to manage like this, can guarantee also simultaneously that some relevant data such as experiment condition, sample parameters all are kept at together, avoided so original the sort of take data after, do not know the necessary shortcomings such as data of some experiments such as experiment condition and sample parameters.In addition, in order to guarantee the versatility of experimental data, we provide the user current data presented can be saved as the function of the text of user's appointment separately with text mode in program.

When this module of design, for data and the outside experimental data measured towards the test module of this program oneself, we change external data based on the data towards self.The user only need be according to creating the project file that new file guide just can be converted to an existing experimental data proportional difference spectrum software easily.

5, data demonstration/print module is looked promptly this module of module is responsible for obtaining data from document module and data based user's selection shown or is printed.Owing to adopted looking of MFC, when printing, can print preview, i.e. What You See Is What You Get function very easily.We have also increased a new function in this module, and that is exactly to allow the user before analysis experimental data to be carried out certain human intervention.Why increasing this function is because in experimentation, tend to occur because external interference makes the obvious higher normal condition of experimental data, the existence meeting of this unusual data point exerts an influence to analysis result, so we allow the user to add manual intervention under the prerequisite that does not change experimental fact, ignore these abnormity point in analytic process.But consider that these points are again to obtain in the experimentation,, just do not use in the analytic process so the point of ignoring still is kept in the document.So just can so that the user recover where necessary.

Concrete operations are as follows: be ready to instrument and equipment and the software that system needs, i.e. one in the above ibm compatible personal computer machine of 486/66/8MB, HP4145B transistor parameter analyzer or one of BC2931A transistor constant measuring instrument, supporting testing cassete or sample stage, software systems according to this structure chart.Wherein, need be between computer and the tester by the appropriate interface card, as gpib interface card.1, is ready to measuring samples; 2, install software systems on computers, concrete way is with reference to this software service manual; 3, connect computer and measuring instrument; 4, install and connect sample box; 5, the various parameters of proportional difference spectrum software are set.Use this software test and analyze, can obtain MOS transistor proportional difference characteristic.

Fig. 6 is the proportional difference characteristic of the mosfet transistor using semiconductor device parameter proportional difference operator analytical technology system and provide.By can determining saturated drain voltage Vdsat easily on the spectrogram, saturation threshold voltage Vtsat and corresponding classical threshold voltage vt ho, its proportional difference result's consistency is fairly good, thereby makes original function obtain strengthening and development.If be applied to the upgrading that instrument must cause instrument.

The invention is not restricted to above-mentioned two examples, for bipolar transistor, junction field effect transistor, SOIMOSFET, the MS diode, heterojunction also is suitable for.Because this is a kind of analytical technology that is of universal significance.

As long as the semiconductor device characteristic that is studied has the characteristics of asymptotic function, just can utilize present technique to carry out characteristic research and Parameter Extraction.

Claims (4)

1, a kind of analyzing parameters of semiconductor system comprises the semiconductor parametric tester device, computer, testboard, computer and tester interface card, the analyzing parameters of semiconductor software systems is characterized in that the complete semiconductor device I-V output characteristic of semiconductor parametric tester device measurement; The analyzing parameters of semiconductor software systems are carried out the proportional difference processing to the I-V characteristic that records, and draw proportional difference I-V function characteristic and semiconductor parameter.

2, analyzing parameters of semiconductor as claimed in claim 1 system is characterized in that described I-V output characteristic comprises the triode service area of semiconductor device, and the asymptotic or accurate asymptotic I-V characteristic of the semiconductor device that obtains of fractional saturation or quasi saturation district.

3, analyzing parameters of semiconductor as claimed in claim 1 system is characterized in that proportional difference constant K value is between 1.01-10.

4,, it is characterized in that described semiconductor software analysis system comprises Subscriber Interface Module SIM as claim 1 or 2 or 3 described analyzing parameters of semiconductor systems; Test module; Analysis module; Data management module; Data demonstration/print module.

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