｜CTIMES Seminar｜Explore New Trends in Validation of WBG Devices: Driving the Green Transformation of Digital Power Supplies

Energy saving and carbon reduction are one of the key strategies for enterprises to achieve sustainable development. By utilizing efficient, energy-saving electronic devices and systems, along with precise digital power supply design, businesses can accelerate their energy conservation and carbon reduction efforts, driving a smoother transition to green transformation. To elaborate on this topic, CTIMES held the seminar "Digital Power Driven Biaxial Transformation: A Green Revolution in Electronic System Development" on 10th September. It intended to concentrate on the development of power components and dissect their architecture and tendencies of electronic system design.

DEKRA iST was invited to attend this seminar. Bobby Hsieh, Technical Manager of the Component Engineering Department, brought the latest insights into the development of WBG (Wide Band Gap) semiconductor technology, " Discussion on Reliability Testing & Measurement Techniques for Wide Band gap Power Device." He delved into emerging WBG semiconductor standards, and what's more, highlighted the importance of selecting the right reliability validation approach for high-performance power systems. His focus underscores how these methods are crucial to enhance system reliability and ensure stable, persistent operation.

Bobby Hsieh first introduced the international standards AEC-Q101 and AQG324 related to power component validation. He then specifically mentioned that during the AEC Workshop in April this year, there will be an exclusive standard for WBG semiconductor design revealed soon. The revision will involve numerous aspects, from wafer to packaging, including H³TRB/ HAST selection, an increase in H³TRB test voltage limit, TCT, IOL, BDOL, Gate Switching Stress, among others. They will further improve the reliability validation standards of power components in different environments.

Further Bobby Hsieh pointed out that in the test project of the power module AQG324, the lifetime testing is carried out under additional dynamic conditions, such as Dynamic Reverse Bias. Therefore, when the switching frequency is greater than 25KHz and under ambient humidity conditions, a dynamic bias voltage is applied to validate the stability of the component. Dynamic gate stress (DGS) testing is employed to evaluate Vth and RDS (on) drift by applying pressure to the gate through voltage changes. The efficiency loss of the module during long-term operation can be determined accordingly.

Bobby Hsieh explained to the guests the methods of dynamic testing, including Double Pulse Test, Switch Test, Short Circuit Withstand Test, and Unclamped Inductive Switching, etc. It is especially recommended that WBG semiconductor and module manufacturers pay close attention to the following two tests: Power Cycling Test (PCT) and Intermittent Operation Life Test (IOL).

• Power Cycling Test (PCT)：There are two types, PCsec and PCmin. The main difference between the two is the parameters of heating time. The heating time of PCsec is set within 5 seconds, while PCmin is defined at more than 15 seconds. Dynamic testing of these parameters allows for the observation of variations in temperature conduction between the chip's interior and the module. This process aids in elevating system reliability as it delivers a more accurate understanding about the thermal behavior of power components.
• Intermittent Operation Life Test (IOL)：Devices are subjected to an on/off cyclic power pulse which heats the device junction to a predefined temperature. It is used to assess the potential failure modes and reliability that may be caused by stress accumulation within the component. This test helps confirm whether the component will perform reliably over the long term under severe operating conditions.

In view of the continuous evolution of high-efficiency technology, power devices will generate a large amount of heat energy when operating at high speeds. If the heat dissipation effect is not ideal, it will easily cause damage to the equipment and its surrounding components. Bobby Hsieh emphasized that thermal resistance testing provides valuable data for in-depth component structure analysis, offering a clear breakdown of the thermal resistance at every layer of the device. In addition, combined with electrical parameter analysis, the safe operation area (SOA) of the power component can be calculated. These testing methods enable non-destructive measurements, reducing sample loss and saving time, while helping to lower R&D expenses and shorten the duration of technical refinements.

Finally, Bobby Hsieh shared with everyone the equipment capacity of DEKRA iST. As technology continuously evolves, we put our focus on providing customers with a comprehensive portfolio of the reliability validation services for WBG power devices. The scope of service covers special high-voltage board design, power component parameter measurement (such as UIS, SC, DPT, Lp), HTRB, HTGB, H³TRB and TST and other related reliability tests. Moreover, an all-round reliability validation solution from components to system is in place to assist customers in assessing the reliability of every aspect of a product. We are standing with them to navigate through a high performance-driven market.