SiC power device reliability test

Challenges and Solutions

The reason why silicon carbide (SiC) is widely used in electric vehicles is that it has three characteristics of "high withstand voltage", "low on-resistance", and "high frequency", which are more suitable for vehicles than silicon-based semiconductors. First of all, from the perspective of material characteristics, silicon carbide (SiC) has lower resistance and less power loss during current conduction, which not only enables more efficient use of electric vehicle battery power, but also reduces the problem of heat generated by traditional high resistance. Reduce the design cost of cooling system.

Secondly, silicon carbide (SiC) can withstand a high voltage of up to 1200V, which reduces the current loss when the silicon-based semiconductor switch is switched, solves the problem of heat dissipation, and also makes the use of electric vehicle batteries more efficient, and the vehicle control design is simpler. Third, silicon carbide (SiC) has better high temperature resistance than traditional silicon-based (Si) semiconductors, and can withstand up to 250 ° C, which is more suitable for the operation of high-temperature automotive electronics.

Finally, the silicon carbide (SiC) chip area has the characteristics of high temperature resistance, high voltage, and low resistance. It can be designed to be smaller. The extra space makes the riding space of electric vehicles more comfortable, or the battery can be made larger to achieve higher mileage.

From the perspective of technological development and progress from silicon-based (Si) to silicon carbide (SiC) MOS, the biggest challenge is to solve the problem of product reliability, and among many reliability problems, the device threshold voltage (Vth) is particularly important. Drift is the most critical, it is the focus of many scientific research work in recent years, and it is also the core parameter to evaluate the technical reliability level of each SiC MOSFET product.

Compared with Si material, the threshold voltage stability of silicon carbide SiC MOSFET is relatively poor, and it also has a great impact on the application side. Due to the difference in crystal structure, compared with silicon devices, there are a large number of interface states at the SiO2-SiC interface, which will cause the threshold voltage to drift under the action of electrothermal stress, and the drift is more obvious at high temperatures, which will seriously affect the device at the system end. application reliability.

According to JEDEC JEP183:2021 "Guidelines for Measuring Threshold Voltage (VT) of SiC MOSFETs", T_CITIIA 109-2022 "Technical Specifications for Silicon Carbide Metal Oxide Semiconductor Field Effect Transistor (SiC MOSFET) Modules for Electric Vehicles", T/CASA 006-2020 "Silicon Carbide Metal Oxide Semiconductor Field Effect Transistor General Technical Specifications" and other requirements, at present, Wuhan PRECISE Instrument has independently developed a series of source meter products like P series pulse source meter ,E series high voltage programmable power supply,HCPL series high current pulse power supply suitable for silicon carbide (SiC) power device threshold voltage testing and other static parameter testing, Covers all current reliability testing methods.