JPS6089770A - Flectional waveform detector for voltage current characteristic of semiconductor device - Google Patents

Abstract

PURPOSE:To detect a flectional waveform efficiently by applying a saw-tooth waveform to a semiconductor device to be measured, and detecting the differential value of a nonlinear waveform outputted from the semiconductor device. CONSTITUTION:A saw-tooth wave generator 1 generates a linear saw-tooth wave repeatedly. The output of the generator 1 is supplied to the semiconductor device 2 to be measured. A differentiator 3 extracts the gradient of the nonlinear output waveform from the device 2 and supplies it to a comparator 4. The comparator 4 converts the gradient of the output waveform from the differentiator 3 into a binary signal. A counter 5 compares the output pulse of the comparator 4 with the number of repetition of the saw-tooth wave and count abnormal waveforms generated by the device 2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for detecting an inflection waveform l of voltage/current characteristics of a semiconductor device.

The voltage/current characteristics of a semiconductor device often exhibit different characteristics depending on the time spent on measurement, mainly due to differences in temperature, and it is not always possible to detect all abnormal inflection points. In order to achieve a high detection rate, it is necessary to completely improve the accuracy of the voltage (current) value used as the power supply to the semiconductor device, especially the accuracy of the voltage (current) value with respect to the time axis when changing it during measurement, and to improve the accuracy of the voltage (current) value as the power supply to the semiconductor device. It is necessary to keep the entire temperature precisely.

The present invention realizes a high detection rate of inflection waveforms without completely improving the accuracy of the power supply to the semiconductor device and without maintaining the temperature of the semiconductor device itself with high precision.

A sawtooth waveform generator according to the present invention, a means for applying output voltage and (current) of the sawtooth waveform generator to all semiconductor devices under test, and a nonlinear waveform output from the semiconductor device under test? a differentiating means for differentiating and extracting a slope; a binarizing means for binarizing the output waveform of the differentiating means; a count number of output pulses of the binarizing means; and a repetition number of the sawtooth wave. A device for detecting inflection waveforms of voltage/current characteristics of a semiconductor device having all the features of a counter for comparison can be obtained.

Next, all the drawings of the embodiment of the present invention will be explained.

FIG. 1 is a block diagram showing one embodiment of the present invention. In FIG. 1, numeral 1 is a sawtooth waveform generator that repeatedly changes voltage (current) in a linear manner, and the output from this device 1 is supplied to a semiconductor device under test. 3 is a differentiator that extracts the entire slope of the nonlinear output waveform from the semiconductor device under test 2, and 4 is a differentiator that extracts the entire slope of the waveform output from the differentiator 3 with a predetermined voltage (current) as a threshold value. It is a comparator that converts into a value.

FIGS. 2(a) to 2(d) show examples of waveforms of each connection line in the above series of operations. Figure 2 (a) is the supply waveform, (b) is the output waveform, (C) is the differential waveform, (d
) are the binarized waveforms shown in FIG. The supply waveform (a) is the waveform supplied from the sawtooth wave generator l to the semiconductor device 2, the output waveform (b) is the waveform output from the semiconductor device 2 to the differentiator 3, and the differential waveform tc) is the waveform from the differentiator 3. The waveform output to the comparator 4, the binarized waveform (d), is the waveform output from the comparator 4.

The supply waveforms are N, N+1, N in the order of the elapsed direction of the time axis t.
+2. N+3. When numbering, N corresponds to Vf, binary waveforms ■ and ■, N+1 corresponds to binary waveforms ■, N+2 corresponds to binary waveforms ■ and ■, and N+3 corresponds to binary waveforms ■ and ■. do. Here, with respect to the supplied waveform N+1, only the binary waveform (2) is generated because no abnormal waveform event occurs in the semiconductor device 1. In Fig. 1, 5 is this two-casing waveform t
d) and the supplied waveform (a) Binarized waveform for complete comparison ■
This is a counter that counts up all the signals from ① and counts down from the supplied waveform N to N+:l. In Fig. 2, the count value in the time width T is 7 (number of binarized waveforms) = 4 (number of supplied waveforms) = 3. For example, if semiconductor 1 does not have an abnormal waveform even once The counter 5 indicates a value of 0.

According to the present invention, it is possible to detect an abnormal inflection waveform with high efficiency when measuring voltage/current characteristics of a semiconductor. Moreover, by setting the time width T=i large, it is possible to easily detect an abnormally inflected waveform even when the probability of occurrence of an abnormally inflected waveform is low.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a waveform diagram of an example of each connection line in a series of operations using the above embodiment. 1... Sawtooth wave generation power supply, 2... Semiconductor device, 3... Differential L 4... Comparator, 5... Counter.

Claims (1)

[Claims] a sawtooth waveform generator; a means for applying an output voltage (current) of the sawtooth waveform generator to a semiconductor device under test;
Differentiating means for completely differentiating the nonlinear waveform output from the semiconductor device under test and extracting all the slopes; and an output waveform of the differentiating means.
A change in voltage/current characteristics of a semiconductor device, characterized in that it includes a binarization means for converting into two values, and a counter for comparing the count number of output pulses of the ZVL conversion means and the number of repetitions of the sawtooth wave. Curved waveform detection device.