Lower-voltage GaN FETs are reducing size, minimizing cooling requirements and improving efficiency.

Lower-voltage GaN FETs (i.e., 100 V) are reducing size, minimizing cooling requirements and improving efficiency for many traditional Si-based power MOSFET applications. In this article, the challenges to repeatably and reliable characterization of the dynamic performance of these devices is discussed. Careful and thoughtful mechanical and electrical design of a customized GaN fixture and test board can overcome many of these challenges, enabling the confident use of these new WBG devices in your power-converter designs.

Power Electronics News
July, 2023
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Transient voltage overshoot is a common phenomenon in GaN high electron mobility transistors (HEMTs) under high slew rate switching conditions. The dynamic parametric instability under such stress is a critical concern for GaN applications. This work, for the first time, accurately characterized the evolution of dynamic on-resistance (R_DS(on)) in GaN HEMTs under repetitive voltage overshoot up to billions of switching cycles. The dynamic R_DS(on) increase was found to be the dominant device degradation under overvoltage switching. Such findings were obtained from a high-frequency, repetitive, unclamped inductive switching (UIS) test with active temperature control and accurate in-situ R_DS(on) monitoring. A physics-based model was proposed to correlate the dynamic R_DS(on) drift with the peak overvoltage, and a good agreement with experimental data was achieved. This model was further used to project the lifetime of GaN HEMTs. For 100 V rated GaN HEMTs switched under 100 kHz and 120 V spikes, the model projects less than 10% dynamic R_DS(on) shift over 25 years of continuous operation. This work addresses the major concerns of overvoltage switching reliability of GaN HEMTs and provides new insights of the electron trapping mechanism.

IEEE Xplore
Ruizhe Zhang, Ricardo Garcia, Robert Strittmatter, Yuhao zhang, Shengke Zhange
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Based on the authors' years of extensive experience, this is an authoritative overview of Wide Bandgap (WBG) device characterization.

EL SEGUNDO, Calif. – September 2018 – Efficient Power Conversion Corporation (www.epc-co.com) announces the publication by the Institution of Engineering and Technology of Characterization of Wide Bandgap Power Semiconductor Devices co-authored by EPC Senior Applications Engineer, Dr. Edward A. Jones. This textbook provides essential tools to assist researchers, advanced students, and practicing engineers in performing both static and dynamic characterization of WBG devices, particularly those based on using silicon carbide (SiC) and gallium nitride (GaN) power semiconductors. The book presents practical considerations for real applications and includes examples of applying the described methodology.