JP2554590B2 - Display method of device characteristic measuring device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for displaying the characteristics of an element to be measured in a graph by using the device characteristic measuring apparatus.

[0002]

2. Description of the Related Art When a DC characteristic or an AC characteristic of a semiconductor device or the like is measured or various parameters are obtained from the measured values, the measurement result is intuitively recognized by an observer. In order to do so, there is a display method that graphs.

FIG. 5 is a graph display example of device characteristics by a conventional display method. In the graph 10, the gate-source voltage V GS vs. drain current ID characteristic 10 of the FET (field effect transistor) and the gate-source voltage V G are shown.
The S vs. mutual conductance gm characteristic 12 is displayed. The gate- source voltage V GS on the horizontal axis is set value 1
The scale is displayed from 0 to 4 volts as shown in 4 and 16, and the 1 scale is 0.5 volts as shown in the set value 18. The vertical axis corresponding to the gate-source voltage VGS vs. drain current ID10 is the set value 20, 22.
As shown in 24 and 24, the scale is displayed from 0 mA to 14 mA, and 2 mA per scale. At this time, the scale 32 of the drain current ID is displayed separately from the scale 34 of the mutual conductance gm. The vertical axis corresponding to the gate-source voltage VGS vs. the transconductance gm12 indicates the scale from 0 to 5 mm, as shown in the set values 26 and 28, and the scale is 0.5 mm as shown in the set value 30. Is. The drain current value is a measured value, and the transconductance value is a calculated value obtained from the gate-source voltage and the drain current.

In the conventional element measuring apparatus, for example, when the characteristics between the gate-source voltage and the drain current are measured and measured, one graph is created and displayed only by these characteristics. In this way, in the conventional device measuring device, the results are displayed on one graph for each measurement item. Therefore, since the scale display on the horizontal axis is also a common value, it is the same graph as the gate-source voltage-drain current characteristic It was not possible to simultaneously display, for example, the drain-source voltage vs. drain current characteristics on the surface.

Further, for example, when it is desired to compare the characteristics of elements of the same type with opposite polarities, it was not possible to display both characteristics on the same graph at the same time, so the graph display had to be switched and the operation was complicated. In addition, it was extremely inconvenient in comparison of characteristics.

An object of the present invention is to provide a display method of an element characteristic measuring device capable of simultaneously superimposing a plurality of graph displays which can independently control the setting of each coordinate axis without switching the graph displays. Is.

Another object of the present invention is to provide a display method of a device characteristic measuring apparatus capable of simultaneously displaying device characteristics of opposite polarity type.

[0008]

According to the present invention, there are provided a first graph display in which first and second variables representing characteristics of a device to be measured are rectangular coordinates, and third and third characteristics representing properties of the device to be measured. An element for displaying the second graph display in which the fourth variable is a rectangular coordinate in an overlapping manner on the screen, and controlling the setting of the coordinate axes of the first, second, third and fourth variables independently of each other. A method of displaying a characteristic measuring device is provided. According to this, it is possible to easily compare the characteristics of the device under test obtained with different measurement items. In addition, the present invention is directed to the first opposite polarities.
When displaying the characteristics of the second element to be measured, a first graph display in which the first and second variables representing the characteristics of the first element to be measured are orthogonal coordinate axes, and a first graph showing the characteristics of the second element to be measured. 1
It is also possible to simultaneously superimpose and display the second variable and the second graph display having the third and fourth variables having opposite polarities as the orthogonal coordinate axes on the display screen. According to this, it is possible to effectively compare the characteristics of the devices to be measured having polarities opposite to each other.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 3 is a block diagram showing the basic construction of the device characteristic measuring apparatus of the present invention. CPU 100 is a bus 102
, Program data in a ROM (Read Only Memory) 104 or input data by operating the input device 106, and according to these data, the bus 10
2 to control other building blocks. Input device 10
6 is an operation panel having push buttons and control knobs,
The input device may be a combination of a display screen and a push button for item selection, or a touch screen using the display screen or other well-known input device. The measurement circuit 108 is a CPU
(Central processing unit) 100 controlled variable voltage source,
It includes at least three measurement units that function as a variable current source, a voltage measurement circuit, and a current measurement circuit and control grounding or opening of a measurement point. Under the control of the CPU 100, the measuring circuit 108 outputs D from the first set of output terminals.
A test signal is supplied to a UT (device under test) 110.

ADC (analog / digital converter) 11
2 is a clock generator 1 controlled by the CPU 100
At the timing of the sampling clock fs from 14, the X and Y analog signals are converted into X and Y digital data, respectively. The X and Y digital data from ADC 112 are stored in memory 116 under address control by CPU 100. The display control circuit 118 displays the characteristics of the DUT 110 on the display device 120 such as a cathode ray tube by using the X and Y digital data read from the memory 116 as horizontal axis data and vertical axis data, respectively.
The DUT 110 is, for example, a bipolar transistor, and by controlling the function of the measurement unit connected to each terminal of the DUT 110, the base-emitter voltage V BE vs. collector current IC characteristic, I CBO-V C.
BO properties, beta-IC characteristics, and selectively measure IC-VBE characteristics other diverse characteristics, independently control the various settings for each coordinate axis and displays superimposed simultaneously display these graphs on the display screen To do.

FIG. 1 is a display example on the display screen of the display device 120 according to the device characteristic display method of the present invention. In the graph 50, the collector current IC of the bipolar transistor of the same element vs. the current amplification factor BETA characteristic curve 52,
Base-emitter voltage VBE vs. collector current IC characteristic curve 54 and base-emitter voltage VBE vs. base current I
The B characteristic curve 56 is displayed.

The horizontal axis of the graph display of the collector current IC vs. current amplification factor BETA characteristic curve 52 has the collector current IC as a variable, and its scale display is displayed at the bottom of the rectangular area. The collector current IC axis scale display shows a range from 0.1 picoampere to 100 milliamperes as shown by the set values 58 and 60, and is a common logarithmic scale as shown by the set value 62. The vertical axis of this graph display is scaled on the left side with the current amplification factor BETA as a variable. The scale display of the current amplification factor BETA shows from minus 20 to 100 as shown by the set values 64 and 66, and is 20 per scale as shown by the set value 68.

The axis of abscissa commonly used for the graph display of the base-emitter voltage VBE vs. collector current IC characteristic 54 and the graph display of the base-emitter voltage VBE vs. base current IB characteristic 56 is the variable base-emitter voltage VBE. Is displayed as a scale on the upper bottom. This base-emitter voltage VCE axis scale display is set value 70 and 7
As shown in 2, indicate from 0 to 0.7 volts,
As shown in the set value 74, it is 0.1 volt per scale. The vertical axis is scaled on the right side with the collector current IC and the base current IB as variables. The scale display of the collector current IC and base current IB axes is from 0.1 picoampere to 1 as shown in the set values 76 and 78.
It shows up to 00 milliamps, and is a common logarithmic scale as shown by the set value 80.

Base-emitter voltage VBE of graph 50
The collector current IC characteristic curve 54 and the base-emitter voltage versus base current IB characteristic curve 56 are measured by the measurement circuit 10.
Although the measured data of the collector current value IC and the base current IB value corresponding to the supplied base-emitter voltage of 8 can be displayed as they are, collector current IC vs. current amplification factor BET
Some characteristics, such as the A curve 52, require calculation. In this case, the CPU 100 performs the calculation.

As described above, by assigning an independent scale display to each of the four sides of the rectangle, superimposing at least two graph displays, and appropriately setting each scale display, a plurality of characteristics of the DUT can be obtained. The comparative measurement of can be performed very easily. Also, like the coordinate axes of IC and IB on the right side, two variables may be assigned and displayed in the same scale display. As a result, three or more graph displays can be displayed in a superimposed manner.

FIG. 2 shows another display example on the screen of the display device 120 according to the device characteristic display method of the present invention. Graph 15
At 0, the collector-emitter voltage VCE vs. collector current IC characteristics 152 and 154 of two types of bipolar transistors of opposite polarities (NPN type and PNP type) are displayed. Each collector-emitter voltage characteristic 152
And 154, the base current was measured 5 times in steps of 1.5 microamperes from 0 microamperes to 7.5 microamperes, 5 times each.
It is represented by the characteristic curve of the book.

The horizontal axis of the graph display of the collector-emitter voltage VCE vs. collector current IC characteristic 152 is scaled at the bottom with VCE as a variable. This collector
The scale display of the emitter-to-emitter voltage VCE shows 0 to -1 volt as shown by the set values 156 and 158, and 0..0 per scale as shown by the set value 160.
It is 1 volt. The vertical axis is scaled on the left side with the collector current IC as a variable. Collector current I
The scale display of the C-axis shows 0 milliampere to minus 1 milliampere as shown by the setting values 162 and 164, and 0.1 per scale as shown by the setting value 168.
It is a milliamp.

The horizontal axis of the graph display of the collector-emitter voltage VCE vs. collector current IC characteristic 154 indicates the collector
The voltage between the emitters VCE is used as a variable for scale display on the upper base. The collector-emitter voltage VCE axis scale display shows 0 to 1 volt as indicated by the set values 170 and 172, and 0.1 volt per scale as indicated by the set value 174. The vertical axis is scaled on the right side with the collector current IC as a variable. The scale display of the collector current IC axis shows 0 milliampere to 1 milliampere as shown by the set values 176 and 178, and 0.1 milliampere per scale as shown by the set value 180.

FIG. 4 is a flow chart showing the operation of the CPU 100 in the characteristic display method of the present invention shown in FIG. In step 200, the setting item information input by the user is read. The setting items are various measurement modes, variables and display ranges of the vertical and horizontal axes of each graph display, selection of linear scale display or non-linear scale display such as logarithmic scale, 1
It is the value per scale. In step 202, the measurement operation is executed according to the information of the setting item, and the obtained measurement data is read. In step 204, the first graph and the second graph are displayed in a superimposed manner based on the set value in step 200. In step 206, it is determined whether or not the display set value of the first graph has been changed. This display set value is information that defines only the display state such as enlarged display and reduced display. Therefore, when only the display set value is changed, it is not necessary to newly execute the measurement operation. If the display set value is changed, the process proceeds to step 208, the display of the first graph is updated based on the changed display set value, and the process proceeds to step 214. If there is no change in step 206, the process proceeds to step 210, and it is determined whether or not there is a change in the display setting value of the second graph. If there is a change, the process proceeds to step 212, and according to the changed display setting value. The display of the second graph is updated, and if there is no change, the process proceeds to the next step 214. In step 214, it is determined whether or not the setting for canceling the current superimposition graph display is made. If the setting for canceling is made, the characteristic display method of the present invention is ended, and if the setting for canceling is not made, step 206 Return to.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the embodiments described herein, and various modifications and changes can be made as necessary without departing from the gist of the present invention. It will be apparent to those skilled in the art that changes can be made. For example, when the display screen is in color, different colors are displayed for each graph display and the corresponding scale display colors are the same, so that the relationship between the scale display and the graph display can be easily grasped. There are also a method of changing the brightness of the display screen for each graph display, a method of displaying a solid line and a dotted line for each graph display, and the like.

[0021]

EFFECTS OF THE INVENTION Since a plurality of graph displays showing the characteristics of the device under test are superimposed and displayed simultaneously, and the setting of variables and scaling of each coordinate axis can be controlled independently, a plurality of different characteristic graph displays are related to each other. This makes it possible to observe and compare at the same time, which is extremely convenient. In particular, this is suitable for a case where a plurality of graph displays measured by supplying signals of different optimum ranges or polarities to the respective elements to be measured are superimposed and displayed for comparison.

[Brief description of drawings]

FIG. 1 is a display example according to a device characteristic display method of the present invention.

FIG. 2 is another display example according to the device characteristic display method of the present invention.

FIG. 3 is a configuration block diagram showing an example of a device characteristic measuring apparatus suitable for applying the present invention.

FIG. 4 is a flowchart showing a procedure of an embodiment of the present invention.

FIG. 5 is a display example of element characteristics by a conventional display method.

[Explanation of symbols]

50 graph 52 collector current IC vs. current amplification factor BETA characteristic curve (first graph display) 54 base-emitter voltage VBE vs collector current IC
Characteristic curve (second graph display) 56 Base-emitter voltage VBE vs. base current IB characteristic curve (third graph display)

Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI technical display location // G01R 13/20 9016-2G G01R 13/20 Z (72) Inventor Osamu Hosoi 5 Kitashinagawa, Shinagawa-ku, Tokyo Masato Hariya, Examiner, Sony Tektronix Co., Ltd. 9-31

Claims (2)

(57) [Claims] 1. A display screen which supplies a test signal of voltage or current to a device under test, measures the current flowing through the device under test or the resulting voltage, respectively, and displays the characteristics of the device under test as a graph on an orthogonal coordinate plane. In the display method of an element characteristic measuring device displayed above, a first graph display in which first and second variables representing characteristics of the device under test are orthogonal coordinate axes, and third and third representing characteristics of the device under test. A second graph display having four variables as Cartesian coordinate axes is simultaneously superimposed and displayed on the display screen, and the setting of the coordinate axes of the first, second, third and fourth variables is controlled independently of each other. A method for displaying a characteristic device characteristic measuring device. 2. A current or a voltage generated in each of the first and second measured elements when a test signal of a voltage or a current is supplied to the first and second measured elements of opposite polarities, and the measured voltage is measured, respectively. In a display method of an element characteristic measuring apparatus for displaying the characteristics of the first and second measured elements as a graph on a rectangular coordinate plane on a display screen, the first and second variables representing the characteristics of the first measured element are The first graph display having a rectangular coordinate axis and the second graph display having a third and fourth variable having polarities opposite to the first and second variables representing the characteristics of the second device under test as a rectangular coordinate axis are displayed. A method for displaying an element characteristic measuring device, which is characterized by simultaneously superimposing and displaying on a screen.