SU362263A1 - ALL-UNION ' - Google Patents

Description

one

The invention relates to the field of electrical measurements of semiconductor devices.

A known method for measuring the derivative of a nonlinear capacitance with respect to voltage, according to which the capacitance under investigation is included in the circuit of the oscillator, an external modulating voltage is applied to it and the frequency change is measured relative to the constant oscillator frequency of the oscillator, which is proportional to the derived nonlinear capacitance with respect to voltage.

However, this method does not provide the possibility of conducting mass tests of devices, since when connecting different devices under study, it is necessary to rebuild the capacitance in the circuit of the oscillator. In addition, when measuring the derivative of a nonlinear capacitance with this method, there is no directly proportional dependence of the output signal value on the derivative value, which introduces additional error in the measurements due to the graduation complexity of the output indicator.

According to the proposed method, in order to increase the accuracy and enable mass measurements along with a constant bias voltage, a low-frequency square-shaped voltage is applied to the capacitance under investigation, and a subsequent voltage is detected that is proportional to the magnitude of the non-linear capacitance derived from the voltage. the device under study. The described method can be carried out using the device shown in the drawing.

The cocTOHJ device from generator /, sensor 2, generator 3, amplifier 4, first detector 5, second detector 6, measuring device 7, resistor 8 and terminals 9 for switching the device under study.

When measuring the derivative of a nonlinear

The capacitance on the device under study is supplied with a constant voltage from sensor 2, a high-frequency voltage of sinusoidal form from generator 3 and a voltage of rectangular form from generator.

The frequency of the square-wave pulses is selected by two or more orders less than the frequency of the generator 3. On the resistor 8, the modulated high-frequency voltage is extracted. The voltage obtained is amplified by the amplifier and detected by detector 5. At the output of detector 6, a constant voltage arises, RR | M | 01Rr01Rr0, 0, DC. The PI of the known magnitude of the low-frequency voltage amplitude AL from the generator 1, the measuring device 7 is graduated in units

magnitude of the derivative of nonlinear capacity with respect to voltage.

In this area, the capacitance of the device under study can be measured by disconnecting the generator / and connecting the measuring device 7 at the output of the detector 5.

Subject invention

The method of measuring the derivative of the nonlinear capacitance of the pn junction by voltage

supplying a high-frequency sinusoidal voltage of small amplitude to the device under investigation, characterized in that, in order to increase the accuracy and ensure the possibility of mass measurements, along with a constant bias voltage, low-frequency rectangular voltage is applied to the device under study and the subsequent two-fold detection constant voltage, proportional to the magnitude of the derivative of the nonlinear capacitance of the voltage of the device under study.