TWI394965B - Method for determining diode parameters by using a diode forward i-v characteristic - Google Patents

Description

Method for obtaining parameters by using the forward bias I - V characteristic curve of a diode

The present invention relates to a method for obtaining a diode parameter by using a forward bias IV characteristic curve of a diode. The present invention particularly relates to a new curve function using a forward bias IV characteristic curve of a diode to illustrate The method of obtaining the parameters directly from the graphical method.

The parameters of the diode can be obtained by using the voltage and current IV characteristic curves of the diode.

For example, according to the thermionic emission theory, the IV ideal curve of the Schottky diode is

Where q is the amount of charge, V is the diode voltage, k is the Boltzmann constant, and T is the absolute temperature.

The saturation current I _s of the Xiaoji diode is

Where A is the contact area and S is the Richardson constant. For energy barrier, β = q/kT , I ₀ = AST ² .

Capturing the energy barrier by using the forward bias characteristic of the diode In the traditional method, the equation (1) is to be taken as a semi-logarithmic pair voltage [semi-logarithmic (Eq. (1)) vs. V plot] that is [semi-logarithmic current-voltage diagram] [ ln I vs. V plot] . After the voltage is slightly larger than 1/ β , the equation (1) is reduced to I = I _s exp( βV ) (2)

In the semi-logarithmic current-voltage diagram is a straight line with a slope of β , and the intercept at zero voltage is I _s . Then, using simple calculations, you can get energy barriers. .

In general, the ideal diode IV curve of equation (1) does not meet the actual characteristics. Another more commonly accepted equation for the diode IV curve is

Where R is the internal series resistance and n is the ideal factor.

After the voltage is slightly greater than 1/ β , the above equation is simplified to

However, the parameters n (ideal factor), R [resistance], and the equation (3) are obtained by the conventional graphic method. [Energy barrier] has two technical difficulties. The first difficulty is that two additional equations are needed for the unknown parameters n and R ; the second difficulty is that R/n must be a constant, an I function or a V function. If the above two technical difficulties are solved, equation (3) becomes

Equation (4) is similar to equation (2). Therefore, its parameters [Energy barrier] can be obtained by the traditional graphic method.

In order to get the parameters , n and R , the scholar Norde assumes that n =1, and suggests a helper function

The above function F has a minimum value for the voltage, so there is a relationship of dF/dV =0 at the minimum value. Use this relationship to export

Where I _min is the current value at which the current is at a minimum value. Obtained when combining equations (4) and (5)

The above equation has the form of equations (2) and (4). Therefore, its parameters [Energy barrier] can be obtained by the traditional graphic method.

For the case of n > 1, many scholars propose various different extraction parameters. method.

Scholar Bohlin modifies Norde's helper function to propose another helper function

Where r is any constant greater than n . Obviously, the function F vs. voltage map [ F ( V ) vs. V plot] has a corresponding function F curve for each r . The equation similar to equation (5) is obtained from the minimum value of the function F curve.

A set of equations can be obtained using two different r values, and the parameters R and n can be generated after the unjoined cubic equation. Then, the parameters [Energy barrier] can be obtained by the traditional graphic method.

Scholars Sato and Yasumura used the Norde method to measure two sets of IV data at two different temperatures to obtain two function F curves. All other Norde-like methods also use the function F to obtain the necessary equations for the existence of the voltage graph [ F ( V ) vs. V plot] and dF/dV =0, and are therefore classified as the Norde method family.

Scholars Cheung and Cheung and scholar Werner proposed another method different from the Norde method family to solve the aforementioned problems. They did not use the auxiliary function F for the parameters R and n . Cheung and Cheung found semi-logarithmic current - voltage plots [V vs. the semi-logarithmic I plot and R] is a straight line having a slope of the Y intercept n / β, which is

Once the parameters R and n are obtained from the above graph, their parameters Obtained by the traditional graphic method.

Werner independently proposed three methods, one of which is the same as the Cheung and Cheung developers. Werner's first method uses the concept of G (small signal conductance) under small signals to avoid the need to draw a class-like Norde diagram. Conductivity is defined as G = dI/dV under small signals. Obtained by the definition of G and the combination of equation (3)

The above equation shows that the G/I versus G graph is a straight line with a Y-intercept of β/n , an X-axis intercept of R, and a slope of -βR/n . Once the parameters n and R are obtained from the above graph, their parameters Obtained by the traditional graphic method.

Werner's other two methods also use the concept of conductivity under small signals, but their reliability and accuracy are slightly worse.

In theory, in order to take out three parameters n , R and The Cheung and Cheung methods and the Werner method require two diagrams, one for taking out the parameters n and R and the other for taking the parameters. .

Scholar MeLean said that it is not easy to obtain the parameters n , R and the simple graphical method when considering other complicated current transmission mechanisms. Therefore, the numerical curve fitting method is developed, and will not be described here.

However, using the graphical method to obtain the parameters n , R and It is the easiest way to use and understand. Although the aforementioned Norde method uses the graphical method to obtain parameters, it is only applicable to the case of n =1. In addition, the aforementioned methods of Bohlin or Sato and Yasumura do not completely take the parameters to obtain the parameters, but also need to solve a set of equations to obtain the parameters. Neither Nord nor Bohlin's method ignores most of the IV data, which applies only to groups of data near the minimum. Therefore, the reliability of the obtained parameter values is not good. In addition, the methods used by the above-mentioned various scholars are merely illustrative of the technical background of the present invention and the state of the art in the past, and are not intended to limit the scope of the present invention.

In view of the above, in order to improve the above disadvantages, the present invention provides a method for obtaining parameters by using a forward bias I - V characteristic curve of a diode, which is a completely new technical method.

At present, the technology related to the diode I - V characteristic curve is only mentioned in a few US patents. For example, US Patent No. 5,406,217, Method of measuring the current-voltage characteristics of a DUT〞; US Patent No. 4,902,912, Appartus including resonant-tunneling device having multiple-peak current-voltage characteristics; US Patent No. 4,456,880 I - V curve Tracer employing parametric sampling; US Patent No. 4,129,823, System for determining the current-voltage characteristics of a photovoltaic array; US Patent No. 4,085,571, Apparatus for measuring the current-voltage characteristics of a TRAPATT diode, and the aforementioned US patents are not The parameters are obtained by using the I - V characteristic curve of the diode. The foregoing U.S. patents are merely illustrative of the state of the art and are not intended to limit the scope of the invention.

The following description is merely illustrative of the preferred embodiments of the invention and the preferred embodiments of the invention. The derivation portion of the diode I - V model function used in the preferred embodiment of the present invention and the parameter acquisition portion using the pictorial method are also described in detail in the [Embodiment].

The main object of the present invention to provide a system using the cis-biased diode IV characteristic curve acquisition parameters of its methods, which proposes a mathematical model function F (n forward bias IV characteristic curve of the diode cis, , R ), and its parameters are obtained completely by the method of illustration, and the present invention achieves the purpose of simplifying the operation of obtaining parameters.

In order to achieve the above object, a method for obtaining a parameter by using a forward bias IV characteristic curve of a diode according to a preferred embodiment of the present invention includes: measuring a forward bias IV characteristic curve of the diode; Model function acquisition a model function to provide an F ( I ) -I map to obtain a diode parameter from the F ( I ) -I map , R , n ; where r is a tunable variable and r is adjusted to be equal to n , ie n = r and obtained Equation; when I =0, get ; R is obtained from the slope [ R / n ] of F ( I ).

Therefore, it only needs to measure the FI relationship in a single pass, without using the dF/dV =0 relationship or an additional solution to a set of equations.

A method for obtaining a parameter by using a forward bias IV characteristic curve of a diode according to another preferred embodiment of the present invention includes: Model function; When the model function is further obtained Model function to provide F ( I ) -I graph; adjust r to equal to the diode parameter n to obtain Equation; where n is equal to r ; when I =0, obtain R is obtained from the slope [ R/n ] of F [ I ].

In order to fully understand the present invention, the preferred embodiments of the present invention are described in detail below, and are not intended to limit the invention.

The method for obtaining the parameters by using the forward bias I - V characteristic curve of the diode of the preferred embodiment of the present invention can be applied to various diodes such as a pn diode or a Schottky diode. However, it is not intended to limit the scope of the invention. The definition of "diode" used throughout the specification of the present invention is not limited to any particular one of the diodes, and will not be described in detail herein.

The method for obtaining the parameters by using the forward bias I - V characteristic curve of the diode in the preferred embodiment of the present invention suitably adopts the mathematical derivation of the diode I - V model function, and the mathematical derivation is only for explaining the present The invention is not intended to limit the scope of the invention.

The method for obtaining the parameters of the forward bias I - V characteristic curve of the diode of the present invention is a computer-executable process, which can be executed on various computer equipment, such as a table. A desktop computer, a notebook, a workstation computer, etc., but are not intended to limit the scope of the present invention.

The following is a brief mathematical derivation of the diode I - V model function used in the preferred embodiment of the present invention. First, the preferred embodiment of the present invention uses a diode forward bias I - V curve function as

Where r is a tunable variable. Combine equations (3) and (6) to obtain

Since r is an adjustable variable, it can be adjusted as needed. When r = n , the first term on the right side of equation (7) is zero, and equation (7) becomes

Equation (8) is a straight line equation having a slope R/n . Therefore, the slope R/n can be obtained by directly measuring the F ( I ) -I map [ F ( I ) vs. I plot]. Once the slope R/n is obtained, the parameters can be obtained by conventional graphical methods. . Alternatively, the parameter of the interception of the current [ I ] axis of the F ( I ) -I diagram can also be used. . Therefore, in the preferred embodiment of the present invention, the method for obtaining the parameters by using the forward bias IV characteristic curve of the diode is to obtain the parameters n , R by a single measurement of the FI relationship. Instead of using a dF/dV =0 relationship or an additional solution to a set of equations, as in the conventional method.

In order to extract the diode parameters by using the forward bias IV characteristic curve of the diode, the present invention defines two preferred embodiments of the present invention by the aforementioned diode IV model function, and is described as follows: The method for obtaining the parameters of the forward bias IV characteristic curve of the diode using the preferred embodiment includes: directly measuring the forward bias IV characteristic curve of the diode; Model function acquisition a model function to provide an F ( I ) -I map to obtain a diode parameter from the F ( I ) -I map , R , n ; where r is a tunable variable and r is adjusted to be equal to n , for example: manual mode or automatically adjusted by computer program r , ie n = r , and obtained Equation; when I =0, get R is obtained from the slope [ R/n ] of F [ I ].

In addition, the method for obtaining the parameters by using the forward bias IV characteristic curve of the diode according to the second preferred embodiment of the present invention includes: Model function; When the model function is further obtained Model function to provide F ( I ) -I diagram; adjust r to equal to the dipole parameter n , for example: manual mode or automatically adjust r by computer program to get Equation; where n is equal to r ; when I =0, obtain ; R is obtained from the slope [ R / n ] of F ( I ).

Obviously, the method for obtaining the parameters by using the forward bias IV characteristic curve of the diode of the present invention only needs to measure IV once, and obtains its characteristic parameters by the following method: resistance R , energy barrier And the ideal factor n . Furthermore, the methods of the first and second preferred embodiments of the present invention are applicable to equations having an IV characteristic curve. The two poles.

Please refer to FIG. 1 , which discloses a method for displaying a function model-current relationship by using a forward bias IV characteristic curve of a diode according to a preferred embodiment of the present invention, which belongs to Xiao Jier. The function model of the polar body - the graph of the current. In Figure 1, the resistance of the Xiaoji diode is R = 101Ω, and the energy barrier is =0.861 eV and ideal factor n = 1.049. The foregoing data is only used to illustrate the experimental results and is not intended to limit the scope of the invention.

Referring again to Figure 1, it shows that when n = 1.047 and n = 1.048, the curve is curved upwards; when n = 1.050 and n = 1.051, the curve is bent downward; when n = 1.049, it is oblique With a slope. Therefore, the present invention only needs to measure IV once, and obtains the resistance R of its characteristic parameter by the graphic method, and the energy barrier is And the ideal factor n .

The foregoing preferred embodiments are merely illustrative of the invention and the technical features thereof, and the techniques of the embodiments can be carried out with various substantial equivalent modifications and/or alternatives; therefore, the scope of the invention is subject to the appended claims. The scope defined by the scope shall prevail.

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Fig. 1 is a graph showing a function model-current relationship using a method for obtaining a parameter of a forward bias I - V characteristic curve of a diode according to a preferred embodiment of the present invention.

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Claims (10)

A method for obtaining a parameter by using a forward bias IV characteristic curve of a diode, comprising: measuring a forward bias IV characteristic curve of the diode; Model function acquisition a model function to provide an F ( I ) -I map to obtain a diode parameter from the F ( I ) -I map , R , n , where For energy barrier, R is the resistance and n is the ideal factor; where r is the tunable variable and r is adjusted to be equal to n , ie n = r and obtained Equation; when I =0, get ; R is obtained from the slope [ R / n ] of F ( I ). A method for obtaining a parameter using a forward bias IV characteristic curve of a diode according to the first aspect of the patent application, which is applied to a pn diode or a Schottky diode. The method for obtaining the parameters by using the forward bias IV characteristic curve of the diode according to the first item of the patent application scope, and obtaining the parameters by the graphic method , R , n . A method for obtaining a parameter using a forward bias IV characteristic curve of a diode according to the first aspect of the patent application, wherein n is obtained by manually adjusting r . A method for obtaining a parameter using a forward bias IV characteristic curve of a diode according to the first aspect of the patent application, wherein n is obtained by automatically adjusting r by a computer program. A method for obtaining a parameter by using a forward bias IV characteristic curve of a diode, comprising: establishing Model function; When the model function is further obtained Model function to provide F ( I ) -I graph; adjust r to equal to the diode parameter n to obtain Equation; where n is equal to r ; when I =0, obtain ; R is obtained from the slope [ R / n ] of F ( I ), where For energy barrier, R is the resistance and n is the ideal factor. A method for obtaining a parameter using a forward bias IV characteristic curve of a diode according to item 6 of the patent application, which is applied to a pn diode or a Schottky diode. The method for obtaining the parameters by using the forward bias IV characteristic curve of the diode according to item 6 of the patent application scope, and obtaining the parameters by the graphic method , R , n . A method for obtaining a parameter using a forward bias IV characteristic curve of a diode according to item 6 of the patent application scope, wherein n is obtained by manually adjusting r . A method for obtaining a parameter using a forward bias IV characteristic curve of a diode according to item 6 of the patent application scope, wherein n is obtained by automatically adjusting r by a computer program.