JPS59125079A - Method for measuring transistor - Google Patents

Abstract

PURPOSE:To measure easily and non-destructively a reverse bias breakdown rating of a bipolar transistor, and to measure a fall time of a collector current by measuring an S parameter of a bipolar transistor to be tested, and executing an operation. CONSTITUTION:A mean impurity density of a base and depth of the base are varied as parameters, and other all design conditions are not varied but are kept constant, by which plural bipolar transistors are manufactured. An S parameter is measured with respect to each of these bipolar transistors. An absolute value of one element S11 of the S parameter is denoted as rho and an angle acute angleS made by S11 is denoted as theta, by which an input reflection coefficient GAMMA is derived by the expression [ I ]. By using the S parameter, the maximum single direction power gain MSG is derived by the expression [II]. In the same way, by using the S parameter, a stable coefficient K is derived by the expression [III]. By using said MSG and K, the maximum competent power gain MAG is derived by the expression [IV].

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to a method for measuring transistors, and in particular, a method for measuring the reverse/polar breakdown strength of a polar polar transistor, and a method for measuring the fall time of a collector current. Regarding. More specifically, the present invention relates to an improvement that makes such measurements simple and non-destructive.

(2) Background of the technology Reverse bias breakdown capability refers to the amount by which the bias i? - It is defined by the collector-emitter voltage and collector current that can be used without destroying the transistor. This is one of the important frame-side factors for Nono Ibora transistors used in switching circuits that include inductance.

Needless to say, it is desirable that this tolerance is as large as possible. On the other hand, the fall time means that when the positive and negative voltages applied to the base of a non-Ibora transistor are reversed to turn off this Non-Ibora transistor, the collector current decreases and as shown in Fig. 1. This is the time it takes to move from point B to point 0. It is desirable that this time be as short as possible.

Knowing these values is absolutely necessary for circuit design using Nono Ibora transistors, and furthermore, since it is a membership fee for improving Nono Ibora transistors, these measurement methods are It is essential and extremely important from an industrial and technological development perspective.

(3) Conventional technology and inverse zebra point/ζ ias Breakdown resistance He and collector current fall time have conventionally been measured in a laboratory using a circuit as shown in FIG. In the figure, 1 is the node to be tested 2-
It is a transistor with t between its collector and emitter.
', ζ electric current 2 and inductance 3 are connected in series,
Further, connected to the base thereof are a reverse/parallel Asumi source 4 and a pulse signal generator 5 for applying a forward pass signal. Note that the diode 6 and the power supply 7 constitute a voltage clamp circuit. In this circuit, when the pulse signal generator 5 applies a positive direction pulse signal to the base of the transistor 1, the transistor 1 is turned on and off as described below. In FIG. 3, vB indicates the base voltage, and the base potential of the transistor 1 is held negative when no pulse is applied, and is inverted to positive only during the period when the pulse is applied. This is the base current, which changes as shown in the figure as the base voltage vB changes. ■
. Reference numeral 8 is a collector current, and when the current flows in the forward direction from the base current, the current flows, and when the current flows in the opposite direction, it stops increasing, decreases, and conversely reaches zero. VZa is the collector
The emitter-to-emitter voltage is low and becomes zero with the generation of collector current, and rises to the voltage specified by the external power supply through a transient phenomenon caused by its decrease. At this time, in the case of polar polar transistors, it is unavoidable that resistance remains in the base region (the electrical circuit connecting the base-pole and the emitter region, and the current path for the base current) during positive inversion. . In this region, especially the emitter-base junction in the center of the emitter region, the emitter-base junction cannot completely become an inverse bias, and charge continues to be injected from this junction, and a width pressure greater than the inductance L is applied to the collector-emitter. 7
When JIl is worn out, the joint becomes locally heated and destroyed. This phenomenon is the reverse bias breakdown capability. I as above
Using a circuit, the collector-emitter current controller C was gradually assisted to destroy the transistor, and the current on the verge of destruction (point A in Figure 1) was measured (the voltage was clamped). The voltage is maintained at a constant voltage value.

). On the other hand, the falling time is the collector current
The time for a to fall (from point B to point 0 in Figure 1) is
In a destructive test using the above-mentioned tapping circuit, the fall time of the collector current under conditions on the verge of destruction was measured using a cathode ray tube oscilloscope or the like.

Therefore, the conventional methods for measuring reverse bias breakdown strength and collector current fall time are laboratory-based, not suitable for industrial use, are not necessarily easy to operate, are inefficient, and are subject to individual differences. , including points that should be improved. In particular, since the measurement of reverse bias breakdown strength is a destructive test, it is extremely unsuitable for industrial use, and this was a drawback that could have been overlooked.

(4) Purpose of the Invention The purpose of the present invention is to eliminate this drawback, and to provide a transistor that has many advantages such as being easy to operate, non-destructive, and suitable for industrial use, especially the reverse of the impolar transistor. It is an object of the present invention to provide a method for measuring the amount of noise breakdown and a method for measuring the fall time of a collector current.

(5) Structure of the Invention The above object is to improve the pace resistance, the fall time of the collector current, and the reverse noise breakdown for each of a plurality of transistors manufactured by changing the impurity concentration of the base and the depth of the base as parameters. 7, find the tj relationship between the base resistance and the reverse negative current breakdown strength, or the relationship between the base resistance and the fall time of the collector current,
Reverse bias breakdown capability of a transistor, characterized by measuring the base resistance of the transistor to be measured, and detecting the reverse bias breakdown capability or collector current fall time of the transistor to be measured according to the above relationship I) and the method of measuring the fall time of the collector current, and the impurity f of the base.
Each of the plurality of transistors fabricated by varying the depth and depth of the pace as parameters has a maximum available power gain, under the collector current ((leather vi 1i-t
J and reverse/ζ ias breakdown Mt are measured, and the relationship between the force gain and the inverse and S ias breakdown withstand capacity or the maximum capacity 1; the relationship between the force gain and the fall time of the collector current is determined. Determine the maximum available power gain of the transistor under test, and from the above relationship, calculate the reverse bias breakdown strength or collector t of the transistor under test.
This is achieved by measuring the reverse bias breakdown resistance and the fall time of the collector current in a transistor, which is characterized by detecting the breakdown time of the base resistance defined in the above configuration. The measurements of jI++w and the maximum available power gain are made as follows.

First, the S-parameter (a 4-element matrix expressed by the following formula) is measured at as many frequencies as possible within the range in which the Ibora transistor under test performs an amplification effect on the input frequency.

By the way, if the absolute value 1 stt + of all is expressed by ρ, and the angle formed by sll/S11 is expressed by θ, then the input reflection coefficient ``is r=ρexP (iθ), and the input impedance zi is, however, zo is the reference value. It is impedance and is usually (equal) [Ω] ↑.

The real component R1n of the input impedance Z1 is expressed as zO(l-ρ2). Since the base resistance rb is equal to the real component of the input impedance, the base resistance can be obtained as follows. - On the other hand, since the maximum available power gain MAG is h4AG = MBG (K-1" -]), it can be found from the above S parameter, and K
(Stable number of cases) is as follows, so this can also be determined from the above S parameter.

The present invention takes advantage of the phenomenon that the reverse bias breakdown capability and the fall time of the collector current are correlated with the base resistance or the maximum available power gain.The process by which this phenomenon was discovered will be briefly described below. .

By changing only the base resistance by changing the emitter width and the number of emitters, we prototyped multiple transistors with all the same wafer processing conditions such as base area and diffusion method, and for each transistor, the base resistance and collector current decreased. After measuring the time, the reverse diaphragm fracture resistance was measured. Then, draw a graph with the base resistance as the X axis and the fall time and reverse bias breakdown capacity as the Y axis, as shown in Figures 4 and 5.
I got the diagram. In the figure, A represents the falling time, and B represents the reverse-to-earth destruction resistance. From the figure, it was confirmed that both the fall time of the collector current and the reverse bias breakdown strength are correlated with the base resistance.

Next, a plurality of transistors similar to those described above were prototyped, and after measuring the maximum available power gain and collector current fall time of each transistor, the reverse noise breakdown withstand capacity was measured.

and the maximum available power gain (measurement frequency is 16 MHz
? be. ] was plotted as the X-axis, and the fall time of the collector current and the inverse noise breakdown capacity were plotted as the Y-axis, and FIGS. 6 and 7 were obtained.

In the figure, C is the fall time of the collector current, and D is the reverse bias breakdown withstand capacity ↑ From the figure, it was confirmed that both the collector current fall time and the reverse bias breakdown capacity are correlated with the maximum available power gain.

Both the fall time of the collector current and the reverse bias breakdown resistance can only be measured using the laboratory method described above. As mentioned above, both the resistance and the maximum available power gain can be determined more easily by measuring the S-parameter and performing simple calculations based on this, which is extremely advantageous. In particular, This is especially true because the measurement of S-parameters can be done unambiguously.
It is. The error between the method of the present invention and the method of the prior art is less than ro (%), which is within an industrially acceptable range.

As explained above, according to the present invention, the S-noise parameter of the bipolar transistor under test is measured, and the reverse bias breakdown strength of the bipolar transistor is destructively measured.
A measurement of the fall time of the collector current can be made.

(6) Embodiments of the Invention Hereinafter, each step of a method for measuring the reverse bias breakdown strength of a Nono Ibora transistor and a method for measuring the fall time of collector current according to an embodiment of the present invention will be further explained.

(a) A plurality of bipolar transistors are manufactured by changing the average impurity level of the base and the depth of the base as parameters, and keeping all the design conditions constant without changing them.

(b) Measure the S-ξ parameter for each of these bipolar transistors.

e→B Absolute value of Harameter's 1st element 811 I S,,
Where I is ρ and the angle /S formed by S11 is θ, the input reflection coefficient ``is determined by the following formula.

= ρexp (iθ) Next, using the input reflection coefficient, the input impedance z1 is determined by the following formula.

1-[ The R-base resistance rb, which is approximately represented by the real component C2 of the input impedance z1, is determined by the following formula.

B) Using the e parameter, the maximum unidirectional power gain MEIG is determined by the following formula.

Similarly, using the S parameter, the stability coefficient K is determined by the following formula.

Using MSG and K, the maximum available power gain MAG is determined by the following formula.

MAG=MSG (K −K” −1) (E) The fall time of the collector current and the inverse curve in the prior art are Destruction withstand capacity is measured, and the relationship as shown in figure fJJ4.5.6.7 is established, that is, the relationship between pace resistance and drop time, the relationship between pace resistance and reverse bias breakdown capacity Q), and the maximum available power gain and collector Find the relationship between the current fall time Q), the maximum available power-gain, and the reverse/reverse-earth breakdown withstand capacity.This relationship is
2 should also apply, and the measurement method 1- of the reverse/semi-irradiation breakdown withstand capacity and the fall time of the collector current according to the present example.
This will serve as standard information.

(f) For the bipolar transistor under test, measure the pace resistance rb and the maximum available power gain (4 A G) using the same process as described in (a) to (b) above. Using the reference information prepared in the process and the pace resistance r1) and/or maximum available power gain MAG of the transistor under test, the reverse noise breakdown withstand capacity and collector current (h fall time) of the transistor under test are calculated. demand.

Kinoda 6 In the example, after determining the reverse-to-direction breakdown strength and the fall time of the collector current, the fall time and the reverse-to-direction breakdown strength were measured using the method in the prior art. The degree of error in the example was confirmed. the result,
It was confirmed that the error in this example was less than 10 cm.

(7) Detailed Description of the Invention According to the present invention, a reverse transistor, especially a non-Ibora transistor, has many advantages such as simple operation, non-destructive operation, suitability for industrial use, etc. A method for measuring bias breakdown strength and a method for measuring fall time of collector current can be provided.

[Brief explanation of the drawing]! Figure 81 shows the curve factor representing the collector wind current characteristics of the ζ Ibora transistor, and Figure 2 shows the circuit used in the prior art to measure the reverse bias breakdown strength and fall time of the Ibora transistor. This is a schematic connection diagram, and the third
The figure is a time chart explaining the operation. Yi 4.
Figure 5 is a graph showing the correlation between pace resistance and descent time, and the correlation between pace resistance and resistance to failure.
The figure shows the maximum effective magnetic force gain and the fall time of the collector,
It is a graph showing the correlation between maximum power gain and reverse bias breakdown capacity. 1... Nono polar transistor, 2.4.7...
Electromagnetic wave, 3... Inductance, 5... Pulse oscillator, 6... Diode, vB... Base voltage, Engineering n.
... Base ωt, xag ... Collector current, VO
K... Collector/emitter electric sweat, A, O... Fall time, BSD... Reverse bias failure 7 + I4 dramatic amount. Fig. 1 Fig. 4 Pace improvement Ueyama beauty Pace resistance (n) Maximum capable electric power

Claims (2)

[Claims] (1) Measure the base resistance, collector current fall time, and reverse bias breakdown strength of each of a plurality of transistors manufactured by varying the base impurity concentration and base depth as a parameter ξ. Find the ratio between the resistance and the reverse bias breakdown capacity, or the rli between the base resistance and the collector current when it falls,
A method for measuring a transistor, comprising: measuring the pace resistance of the transistor to be measured, and detecting the reverse bias breakdown strength or the fall time of the collector current of the transistor to be measured from the above relationship. (2) Measure the maximum available power gain, collector current fall time, and reverse bias breakdown capability of each of multiple transistors manufactured by varying the base impurity concentration and base depth k as parameters, and Find the relationship between the available gravity gain and the inverse, 6-year breakdown withstand capacity, or the relationship between the maximum available power gain and the fall time of the collector current, and measure the maximum available power gain of the transistor under test to determine the above relationship. A method for measuring a transistor, which comprises detecting the reverse bias im resistance t or the fall time of the collector current of the transistor to be measured.