The on state characteristics, blocking characteristics, and operating temperature of IGBT devices are closely related, and the static characteristics of IGBTs with different structures also vary with temperature.
1. The influence of temperature on the on state characteristics of IGBT
The collector current of IGBT is divided into two parts: one is the hole current injected from the P+collector region to the n-drift region and flowing through Pwell to the emitter; The second is the electron current injected from the n+emitter region through the channel into the n-drift region.
For PT-IGBT, the current amplification factor of the pnp transistor on its collector side is relatively high, resulting in a relatively large hole current. Therefore, the saturation voltage drop of PT-IGBT devices has a negative temperature coefficient, that is, the higher the temperature, the lower the saturation voltage drop.
Because the P+collector region of PT-IGBT is relatively thick, the number of holes injected during conduction is relatively large, and the number of holes that need to be extracted during shutdown is also relatively large, resulting in a slower shutdown speed. In order to improve the turn off speed, carrier lifetime control technology is needed to reduce the minority carrier lifetime. However, due to the increasing lifetime of minority carriers with temperature and the prolonged duration of conductivity modulation effect, the saturation voltage drop of the device decreases, while the turn off time increases.
For NPT-IGBT and FS-IGBT, due to the thin back collector region and relatively low doping, they belong to transparent collectors. The current amplification factor of PNP transistors on the collector side is low, and the electron current is greater than the hole current. Therefore, the saturation voltage drop of these two transistors has a positive temperature coefficient. The use of transparent collector design can achieve fast device shutdown without the need for carrier lifetime control, and the n-drift region of FS-IGBT is thinner, resulting in lower saturation voltage drop.
2. The Effect of Temperature on IGBT Blocking Characteristics
The blocking voltage and leakage current of IGBT are closely related to temperature: as the temperature increases, the internal lattice vibration of the device intensifies, and the probability of carrier lattice collision increases. So if there are sufficient collision ionization conditions for breakdown, a higher electric field is necessary to enable the carriers to obtain sufficient energy. Therefore, as the temperature increases, the avalanche breakdown voltage of the PN junction will increase. Moreover, due to the influence of temperature on the current amplification factor of PNP transistors, the blocking voltage and leakage current of IGBT will change with increasing temperature.
3. The Effect of Temperature on IGBT Threshold Voltage
For IGBT, as the temperature increases, the characteristic curve of the device will shift. As the temperature increases, the threshold voltage decreases, mainly because as the temperature rises, the bandgap width narrows and the channel inversion generates free electrons relatively more easily. The narrowing of the bandgap width with increasing temperature is due to the fact that as the temperature rises, lattice vibrations intensify, crystal atomic spacing increases, and the control of electrons outside the nucleus weakens. Electrons are more likely to break free from the constraints of the nucleus and become free electrons, reflected in the energy band where the energy value at the top of the valence band increases and the energy value at the bottom of the conduction band decreases, resulting in a decrease in the bandgap width.
The Temperature Forcing Systems developed by ZONGLEN has become the core equipment for IGBT (Insulated Gate Bipolar Transistor) characteristic analysis and temperature verification through ultra fast temperature rate, precise temperature control, and pure mechanical refrigeration technology. Its applications cover scenarios such as cold and hot shock testing, failure analysis, live testing, and production line batch verification, significantly improving testing efficiency and reliability.
Temperature Forcing Systems has a wider temperature range of -70 ° C to+225 ° C, providing highly advanced temperature conversion testing capabilities. The temperature conversion takes about 10 seconds from -55 ℃ to+125 ℃; After long-term multi condition verification, it meets the requirements of various production and engineering environments. Temperature Forcing Systems is a pure mechanical refrigeration system that does not require liquid nitrogen or any other consumable refrigerants.
Temperature Forcing Systems covers the full lifecycle testing of IGBT
1. Extreme working condition simulation
Cold start test: Simulate the starting process of a vehicle in an extremely cold environment of -40 ℃ to verify the thermal stress resistance of IGBT packaging materials, solder joints, and chips.
Full load operation test: Continuously apply rated current (such as 600A) at a high temperature of 175 ℃, monitor module failure time, and ensure high temperature stability.
2. Fatigue life verification
Through cyclic impact from -40 ℃ to+175 ℃ (e.g. 1000 cycles, 15 minutes per cycle), potential defects such as weld cracking and delamination are accelerated and exposed, meeting automotive standards such as AEC-Q101 and AQG-324.
3. Live testing capability
Traditional ovens cannot achieve live testing under high or low temperature conditions, while high and low temperature impact airflow meters can support online testing to directly evaluate the performance of IGBTs in actual working conditions.
4. Failure analysis assistance
By combining X-ray detection and acoustic scanning (SAT) after temperature shock, precise positioning of internal defects in the package (such as solder micro cracks and delamination) can be achieved, providing a basis for design improvement.

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