Industry trends

IGBT and its application development

IGBT (Insulated Gate Bipolar Transistor) is the core device of power control and power conversion. It is a composite full-control voltage-driven power semiconductor device composed of BJT (Bipolar Transistor) and MOS (Insulated Gate Field Effect Transistor). , has the characteristics of high input impedance, low conduction voltage drop, high-speed switching characteristics and low conduction state loss, and occupies a dominant position in high-frequency and medium-power applications.

At present, IGBT has been able to cover the voltage range from 600V to 6500V, and its applications cover a series of fields from industrial power supplies, frequency converters, new energy vehicles, new energy power generation to rail transit, and national grid.

Main test parameters of IGBT power semiconductor devices

In recent years, IGBT has become a particularly eye-catching power electronic device in the field of power electronics, and has been more and more widely used, so the test of IGBT has become particularly important. The test of IGBT includes static parameter test, dynamic parameter test, power cycle, HTRB reliability test, etc. The most basic test in these tests is static parameter test.

IGBT static parameters mainly include: gate-emitter threshold voltage VGE(th), gate-emitter leakage current IGEs, collector-emitter cut-off current ICEs, collector-emitter saturation voltage VCE(sat), freewheeling Diode voltage drop VF, input capacitor Ciss, output capacitor Coss, reverse transfer capacitor Crss. Only when there is no problem with the static parameters of the IGBT, can the dynamic parameters (switching time, switching loss, reverse recovery of the freewheeling diode), power cycle, and HTRB reliability be tested.

Difficulties in testing IGBT power semiconductor devices

IGBT is a composite fully-controlled voltage-driven power semiconductor device composed of BJT (bipolar transistor) and MOS (insulated gate field effect transistor), which has the advantages of high input impedance and low conduction voltage drop; at the same time The IGBT chip is a power electronic chip, which needs to work in the environment of high current, high voltage and high frequency, and has high requirements on the reliability of the chip. This brings certain difficulties to IGBT testing:

1. IGBT is a multi-port device, which requires multiple instruments to be tested together;

2. The smaller the leakage current of the IGBT, the better, and high-precision equipment is required for testing;

3. The current output capability of the IGBT is very strong, and it is necessary to quickly inject a 1000A current during the test and complete the sampling of the voltage drop;

4. The withstand voltage of IGBT is relatively high, generally ranging from several thousand to ten thousand volts. It is necessary for the measuring instrument to have the ability of high voltage output and nA level leakage current test under high voltage;

5. Since the IGBT works under a strong current, the self-heating effect is obvious, and it is easy to cause the device to burn out in severe cases. It is necessary to provide a μs level current pulse signal to reduce the self-heating effect of the device;

6. The input and output capacitance has a great influence on the switching performance of the device. The equivalent junction capacitance of the device is different under different voltages, so C-V testing is very necessary.

Precise IGBT power semiconductor device static parameter test solution

Precise IGBT power device static parameter test system integrates a variety of measurement and analysis functions. It can accurately measure the static parameters of IGBT power semiconductor devices. Supports measurement of junction capacitance of power devices in high-voltage mode, such as input capacitance, output capacitance, reverse transfer capacitance, etc.

Precise power device static parameter test system mainly includes test host, test line, test fixture, computer, host computer software, and related communication and test accessories. The modular design and test methods are flexible, which can greatly facilitate users to add or upgrade measurement modules, and adapt to the changing needs of measuring power devices. The whole system adopts the test host independently developed by Proceed, with built-in voltage, current and capacitance measurement unit modules of various specifications. Combined with the dedicated upper computer test software, different parameters such as voltage and current can be set according to the needs of the test project to meet different test requirements. Test data can be saved and exported, and I-V and C-V characteristic curves can be generated. In addition, the test host can be used in conjunction with the probe station to realize wafer-level chip testing; it can also be used in conjunction with high and low temperature boxes, temperature control modules, etc. to meet the needs of high and low temperature testing.

The voltage and current measurement units used inside the test host adopt multi-range design, and the test accuracy is 0.1%. Among them, the gate-emitter supports a maximum of 30V@10A pulse current output and testing, and can test leakage currents as low as pA; the collector-emitter supports a maximum of 6000A high-speed pulse current, with a typical rise time of 15μs and a voltage High-speed synchronous sampling function; up to 3500V voltage output, and built-in leakage current measurement function; frequency up to 1MHz. Support one-click test of all national standard indicators.

Among them, Precise Instruments focuses on the domestic substitution needs of the third-generation advanced semiconductor scientific instruments as the key research direction. It has very strong design and development capabilities for high-voltage source measurement units required for static parameter testing of power devices such as IGBTs, and can continue to meet market demands. 3KV, 5KV, 10KV test requirements.

The E series high-voltage programmable power supply launched by Precise Instruments has the characteristics of high output and measurement voltage (0-3500V, expandable to 10kV), output and measurement of weak current signal (1nA), and output and measurement current of 0-100mA.

The device works in the first quadrant, and the product can measure current synchronously, support constant voltage and constant current working mode, and support rich IV scanning modes. E series high-voltage programmable power supply can be used in IGBT breakdown voltage test, IGBT dynamic test bus capacitor charging power supply, IGBT aging power supply, lightning protection diode withstand voltage test and other occasions. Its constant current mode is of great significance for quickly measuring the breakdown point.

In addition, for the test occasions requiring high current such as diodes, IGBT devices, and IPM modules, Pusyce HCPL series high-current pulse power supplies have large output current (1000A), steep pulse edges (15μS), and support two-way pulse voltage measurement ( Peak sampling) and support for output polarity switching. The equipment can be used in testing occasions requiring high current such as Schottky diodes, rectifier bridge stacks, IGBT devices, IGBT half-bridge modules, and IPM modules. Using this equipment can independently complete the "current-on-voltage" scanning test.

IGBT static test fixture solution

For different package types of IGBT products on the market, Proces can also provide a complete set of fixture solutions, which can be used for testing TO single-tube, half-bridge modules and other products.

After more than 20 years of rapid development, major domestic third-generation semiconductor companies have basically formed a complete industrial chain, and the industrial scale has reached the world's largest. The three main areas of application are optoelectronic devices, such as semiconductor lighting, laser display, etc.; radio frequency electronic devices, such as mobile communication base stations, satellite communications, etc.; power electronic devices, such as new energy vehicles, smart grids, high-speed rail transit, etc.

Focusing on the R&D and innovation of electrical performance testing equipment from materials and wafers to semiconductor devices, Precise has been deeply involved in the field of semiconductor testing and has accumulated rich experience in I-V testing. It has successively launched DC source measure meters, pulse source measuring units, and high-current pulse meters. Test equipment such as source measure units and high-voltage source-measurement units are widely used in scenarios such as university research institutes, laboratories, new energy, photovoltaics, wind power, rail transit, and inverters.