TWI415203B - Method for obtaining parameters by using reverse iv characteristic of diodes - Google Patents

Abstract

The embodiment for determining parameters by using reverse I-V characteristic of diodes includes the steps of: building a model function, measuring reverse I-V characteristics of diode, and a dF(I)/dI-I characteristic curve by utilizing a function of, wherein the dF(I)/dI-I characteristic curve can be fit the measured reverse I-V characteristic of diodes by adjusting a adjustable parameter r and a ideal factor n. Moreover, the barrier height can be derived while I=0, and the resistance R can be derived by the slope of dF(I)/dI of the dF(I)/dI-I characteristic curve.

Description

Method for obtaining parameters of a reverse bias I-V characteristic curve of a diode

The present invention relates to a method for obtaining a diode parameter, and more particularly to a method for obtaining a diode parameter using a reverse bias IV characteristic curve of a diode.

A diode is an electronic component that allows current to flow only through. The earliest diodes consist of a vacuum tube or a tube containing a low-pressure gas. There are two thin wires in the tube - the screen and the filament. The electrons can only run from the filament to the screen in one direction, so that the current can be limited. direction. With the development of electronic components, the application of diodes is quite extensive, especially laser diodes, which can emit laser light as an indicator. The use of a diode can be used to convert alternating current into direct current. Photocells are a variant of a diode that can sense changes in light or other rays and enhance and amplify the amount of light. In addition, it can emit light or other rays. The diode can obtain the parameters of the diode by using the voltage and current IV characteristic curves of the diode.

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 curve of the Schottky diode is:

among them For energy barrier, n is the ideal factor, V _d is the voltage across the diode, β = q / kT , I ₀ = AST ² .

Where q is the amount of charge, k is the Boltzmann constant, T is the absolute temperature, A is the contact area, and S is the Richardson constant.

In the past, scholars Norde, Bohlin, and other scholars have proposed a number of methods to obtain the relevant IV characteristic parameters of the Xiaoji diode, but the method is generally only applicable to the forward bias characteristics of the diode. In fact, many applications of the Schottky diode often operate in a reverse bias state. For example, a metal-semiconductor-metal (MSM) photodetector is formed by two Schottky diodes in a back-to-back connection. When biased, it has the reverse bias characteristic of the Schottky diode.

In order to get the parameters , n and R , scholar Norde proposed a helper function:

Among them, only one measurement method can be used to obtain parameters under the fixed temperature. [Energy barrier] and R [resistance].

Scholar Bohlin uses Norde's helper function to propose another helper function:

Where r is any constant greater than n .

Both the Nordian and Bohlin IV curve functions assume that r is a constant, and r is equal to 2 in Nord's IV curve function, and r is an arbitrary constant in Bohlin's IV curve function. However, neither the Norde nor Bohlin's method is suitable for direct analysis of the reverse bias IV curve. First, when I is negative, the IV curve function F ( V ) does not apply. Second, the IV curve characteristic of equation (1) does not help to establish a new relationship. Finally, equation (1) is not completely correct. That is, equation (1) fails to show the reduction of the ideal factor n The energy barrier can equally affect the rate at which electrons drift from the metal to the semiconductor or from the semiconductor to the metal.

In short, the Norde or Bohlin method using the forward bias IV characteristic curve function F ( V ) of the diode to obtain its parameter method is not suitable for analyzing the reverse bias IV characteristic curve.

At present, the technology of the diode IV characteristic curve is only mentioned in a few U.S. patents, for example: US Patent Publication No. 5,406,217, Method of measuring the current-voltage characteristics of a DUT〞; US Patent Publication No. US 4,902,912 〝Apparatus including resonant-tunneling device having multiple-peak current-voltage characteristics〞; US Patent Publication No. US 4,456,880 〝 IV curve tracer employing parametric sampling〞; US Patent Publication No. US 4,129,823 〝System for determining the current-voltage characteristics of a photovoltaic array "; US Patent Publication No. US4,080,571 of" Apparatus for measuring the current-voltage characteristics of a TRAPATT diode ", and on the aforesaid U.S. Patent no IV characteristic curve on the use of the diode takes its parameter.

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 IV model function employed in the preferred embodiment of the present invention and the portion of the parameters obtained by the illustrated method are further described in detail in the embodiments.

The main object of the present invention provides a system utilizing a reverse bias of diode IV characteristic curve acquisition method of its parameters, the mathematical model in which the function F (n IV characteristic curve of the diode reverse biased, , R ), and obtain its parameters by the graphical method, 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 reverse bias IV characteristic curve of a diode according to a preferred embodiment of the present invention includes: establishing a model function; measuring a reverse bias IV characteristic curve of the diode; and utilizing One program obtains a dF(I)/dI-I characteristic curve; wherein the dF(I)/dI-I characteristic curve and the reverse bias IV characteristic curve of the partial measuring diode are adjusted by adjusting a tunable variable r is approximated by an ideal factor n , and in addition, when I =0, an energy barrier value is obtained. And a resistance value R can be obtained by the slope of dF(I)/dI in the dF(I)/dI-I characteristic curve.

The above and other objects, features, and advantages of the present invention will become more apparent and understood.

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 reverse bias IV characteristic curve of the diode in the preferred embodiment of the present invention can be applied to various diodes such as a pn diode or a Schottky diode, but it is not It is 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 reverse bias IV characteristic curve of the diode in the preferred embodiment of the present invention suitably adopts the mathematical derivation of the diode IV model function, which is only used to illustrate the feasibility of the present invention. It is not intended to limit the scope of the invention.

The method for obtaining the parameters of the reverse bias IV 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 desktop computer. [desktop computer], notebook computer, workstation computer, etc., but it is not intended to limit the scope of the present invention.

The mathematical derivation of the diode IV model function employed in the preferred embodiment of the present invention is described below for establishing the model function of the present invention:

Where V _d = V -IR, when - βV _d >>1, the above equation can be simplified as:

The preferred embodiment of the present invention employs a helper function as:

Combine equations (3) and (4) to obtain:

Where r is a tunable variable, It is an energy barrier, n is an ideal factor, V is a voltage value, R is a resistance value, and I is a current value.

According to formula (5), when I is 0, by adjusting the adjustable variable r to the ideal factor n , 1/r≒1/n, the energy barrier value F(r, V, I) is obtained. .

Differentiating the current by equation (5) gives:

Available from equation (3):

Combining equation (6) with equation (7), you can get:

Since r is an adjustable variable, it can be adjusted as needed. Wherein, a hyperbolic relationship is formed between dF(I) / dI-I , and the curves formed by each of the two dF(I) / dI are not mutually staggered. In addition, in the part of -βV _d >> 1 , it is known that dF(I) / dI has a constant term (1/ r -1) R , and dF(I) / dI can be found by plotting I , dF (I) / dI form a horizontal line. On the other hand, when r is greater than (or less than) n , the horizontal line formed by the dF(I) / dI is bent upward (or downward). In addition, adjust r to equal to n , for example: manual mode or automatically adjust r by computer program, ie n = r , and get the following formula:

Next, the measurement of the reverse bias IV characteristic curve of the diode is performed. The commonly used measuring instrument is the HP4145B DC measuring system. After obtaining the measured data, the equation derived by the above derivation is used. , can draw dF (I) / dI characteristic curve. By adjusting the adjustable variable r and the ideal factor n , the dF(I) / dI-I characteristic curve is approximated to the reverse bias IV characteristic curve of the partial measuring diode. Also, in the equation When I is close to 0, it will bend downward or upward, and the energy barrier value It can be obtained by the intercept of I equal to zero. In addition, the IV characteristic curve of the reverse bias voltage of the measuring diode is approximated by the equation, and the resistance R can be obtained by the graphic method.

In order to understand the implementation process of the first embodiment more clearly, the following steps can be further explained:

Step 1: Create a model function .

Step 2: Obtain the quadrupole reverse bias IV characteristic curve from the measurement.

Step 3: By adjusting the adjustable variable r and the ideal factor n , one program can be obtained.

Step 4: The dF(I) / dI-I characteristic curve is approximated to the reverse bias IV characteristic curve of the partial measuring diode.

Step 5: By equation , when I =0, the energy barrier value is obtained. .

Step 6: By equation The resistance value R can be obtained by the dF(I) / dI-I curve characteristic.

Obviously, the method for obtaining the parameters by using the reverse bias IV characteristic curve of the diode of the present invention only needs to measure IV once, and only needs to obtain its characteristic parameters by the following method: resistance R , energy barrier And the ideal factor n . Furthermore, the method of the preferred embodiment of the present invention is applicable to an equation having an IV characteristic curve. The two poles.

Referring to FIG. 1 , a method for displaying a model function-current relationship using a reverse bias IV characteristic curve of a diode according to a preferred embodiment of the present invention is disclosed, which is a Xiaoji dipole. The model function of the body - the graph of the current. In Fig. 1, the contact area of the Xiaoji diode is A = 1 cm ² , the Richardson constant is S = 120 A / ° K cm ² , the temperature is T = 300 ° K, the resistance is R = 10 Ω, and the energy barrier is =0.79 eV and ideal factor n = 1.3. 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 r = 1.5 and r = 1.4, the curve bends upwards; when r = 1.2 and r = 1.1, the curve bends downward; when r = 1.3, it shows one Horizontal line. 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 .

Referring to FIG. 2, a method for obtaining a parameter of a model function-current with 0.1% electronic noise by using a reverse bias IV characteristic curve of a diode according to a preferred embodiment of the present invention is disclosed. It is a model function of the Xiaoji diode and a graph of current. The graph shows that when r = 1.5 and r = 1.4, the curve is curved upwards; when r = 1.2 and r = 1.1, the curve is bent downward; when r = 1.3, it is a horizontal line. Therefore, the model function having a 0.1% electronic noise with a slope still has a curve characteristic conforming to the theory, and the resistance R having the characteristic parameter of 0.1% electronic noise can be obtained by the graphic method, and the energy barrier is And the ideal factor n .

Referring to Table 1, it is disclosed that the method for obtaining the parameters of the reverse bias IV characteristic curve of the diode by using the preferred embodiment of the present invention is obtained, and the model of adding and not adding the different diodes to the electronic noise is obtained. Function-current series resistance value. Where R _i is the series resistance value under different test conditions, i =1 is no electronic noise added, i = 2 is 0.1% electronic noise, and the model function-current d F(V)/II diagram can be respectively Refer to Figure 1 and Figure 2.

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.

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

Fig. 2 is a graph showing the relationship between the model function and the current with 0.1% electronic noise using the reverse bias IV characteristic curve of the diode in the preferred embodiment of the present invention.

Claims (8)

A method for obtaining a parameter by using a reverse bias IV characteristic curve of a diode, comprising the steps of: establishing a model function; measuring a reverse bias IV characteristic curve of a diode; and obtaining a dF by using a program /dI-I characteristic curve; wherein the reverse bias IV characteristic curve of the dF/dI-I characteristic curve and the partial measuring diode is approximated by adjusting an adjustable variable r and an ideal factor n , , the model function is And r is a tunable variable, For the energy barrier, n is the ideal factor, V is the voltage value, R is the resistance value, and I is the current value. When I =0, an energy barrier value is obtained. And a resistance value R can be obtained by the dF/dI slope in the dF/dI-I characteristic curve. The method of claim 1, wherein the model function is for an IV characteristic having an electronic noise of 0.1% or less. The method of claim 1, wherein the equation is derived using the model function. The method of claim 1, wherein the equation is The method of claim 1, wherein the method is applicable to a pn diode. The method of claim 1, wherein the adjustment variable r and the adjustment factor n are adjusted in an incremental manner. The method of claim 1, wherein the adjustment variable r and the adjustment factor n are adjusted in a decreasing manner. The method of claim 1, wherein the adjustable variable r and the ideal factor n are adjusted by a computer program.