Drain leakage current testing circuit and method in field effect transistor breakdown voltage characteristic

Abstract

The invention discloses a drain leakage current testing circuit and method in a field effect transistor breakdown voltage characteristic. The circuit comprises a test voltage source and a tested fieldeffect transistor; a current / voltage conversion amplification module is arranged between a positive electrode of the test voltage source and a drain D of a field effect transistor; a voltage output signal of the current / voltage conversion amplification module is transmitted to a signal input end of an isolation amplifier module; the current / voltage conversion amplification module is composed of an operational amplifier and a sampling resistor; and an isolation output end of the isolation amplifier module is connected to a microprocessor unit. A current-voltage conversion circuit is used to replace a directly arranged ammeter on the drain side, a set of voltmeter test hardware is used to be connected to the current-voltage conversion circuit to realize the test of the leakage current; thedrain leakage current testing circuit is simple, is high in test precision, can achieve parallel test of N tested devices in a multi-station condition on the basis of one set of voltmeter test hardware, can improve the test precision and efficiency, and can save the hardware cost.

Description

technical field [0001] The invention belongs to the field of circuit testing of discrete devices, and in particular relates to a drain leakage current testing circuit and method in field effect tube breakdown voltage characteristics. Background technique [0002] In the field of integrated circuit testing, various types of MOSFETs or other discrete devices need to be tested for leakage between device pins. When the device under test has the characteristics of high breakdown voltage, it is necessary to input a high voltage to test the device. Perform measurements (such as: the first generation Si silicon-based MOSFET and the third generation semiconductor device GaN gallium nitride field effect transistor silicon, etc.). [0003] MOSFET type (the MOSFET corresponding to the first generation semiconductor material Si silicon, when measuring the leakage current, can be connected to the S terminal (source) of the device for measurement; but the discrete device corresponding to t...

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Problems solved by technology

[0003] MOSFET type (the MOSFET corresponding to the first generation semiconductor material Si silicon, when measuring the leakage current, can be connected to the S terminal (source) of the device for measurement; but the discrete device corresponding to the third generation semiconductor material GaN, the current test requirements It is to measure the leakage current at the D terminal) The technical requirement for the device to measure the leakage is to test the current at the D terminal (drain). The simplest test method used is as follows: figure 1 , connect an ammeter between the voltage source and the DUT (drain), and obtain the current at the D terminal by reading the value of the ammeter. However, due to the high common-mode voltage and the nA level of the measured current, this measurement method requires Ammeters have very high accuracy, but there are not many ammeters that meet such environmental and accuracy requirements, and they are expensive

[0004] for figure 1 In the technical solution shown, since this type of device has the characteristics of high breakdown voltage, it needs to input a high voltage (for example, about 650v) during the test, which results in a high common mode situation, but in the case of high common mode, When the measured current is very small (such as nA nanoampere level), the measurement accuracy cannot be guaranteed due to high common-mode interference

Therefore, those skilled in the art devised another technical scheme, such as figure 2 , Connect ammeters in series at the G-terminal and S-terminal of the device, measure the current at the G-terminal (gate) and S-terminal (source), and then add the currents at both ends to calculate the current at the D-terminal, in this way Compared figure 1 The technical solution reduces the requirements for the input range of the common mode voltage of the ammeter, and switches from the D terminal to the G terminal and the S terminal for measurement, but this method does not follow the technical requirements for the measurement at the D terminal, and the obtained value is not in the D terminal. Due to the actual measurement at the terminal, due to certain errors in the measurement, the error of the final value obtained by adding two values ​​with errors will be greater

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