This article presents the cryogenically cooled application for wide bandgap (WBG) semiconductor devices. Characteristics of silicon carbide (SiC) and gallium nitride (GaN) at cryogenic temperatures are illustrated. SiC MOSFETs exhibit increased on-state resistance and slower switching speed at cryogenic temperatures. However, cryogenic cooling provides low ambient temperature environment and thus enables the SiC converter to operate at lower junction temperature to achieve higher efficiency compared to room temperature cooling. A cryogenically cooled MW-level SiC inverter prototype is developed and demonstrated the feasibility of operating high-power SiC converter with cryogenic cooling. GaN HEMTs exhibit more than five times on-state resistance reduction and faster switching speed at cryogenic temperatures which makes GaN HEMTs an excellent candidate for cryogenic power electronics applications. The significantly reduced on-state resistance of GaN devices provides the possibility to operate them at a current level much higher than rated current at cryogenic temperatures. A GaN double pulse test (DPT) circuit is constructed and demonstrated that GaN HEMTs can operate at nearly four times of rated current at cryogenic temperatures. Challenges of utilizing WBG device with cryogenic cooling are discussed and summarized.

中文翻译：

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低温冷却的SiC和GaN器件

本文介绍了宽带隙（WBG）半导体器件的低温冷却应用。说明了低温下的碳化硅（SiC）和氮化镓（GaN）的特性。SiC MOSFET在低温下表现出更高的导通电阻和较慢的开关速度。然而，低温冷却提供了较低的环境温度环境，因此与室温冷却相比，SiC转换器能够在较低的结温下工作以实现更高的效率。开发了低温冷却的MW级SiC逆变器原型，并演示了使用低温冷却运行大功率SiC转换器的可行性。GaN HEMT在低温下的导通电阻降低了五倍以上，开关速度更快，这使得GaN HEMT成为低温功率电子应用的极佳候选者。GaN器件的导通态电阻显着降低，这使它们有可能在远低于低​​温下的额定电流的电流水平下运行。构建了GaN双脉冲测试（DPT）电路，并证明了GaN HEMT在低温下的工作电流几乎是额定电流的四倍。讨论和总结了在低温冷却条件下使用WBG设备的挑战。GaN器件的导通态电阻显着降低，这使它们有可能在远低于低​​温下的额定电流的电流水平下运行。构建了GaN双脉冲测试（DPT）电路，并证明了GaN HEMT在低温下的工作电流几乎是额定电流的四倍。讨论和总结了在低温冷却条件下使用WBG设备的挑战。GaN器件的导通态电阻显着降低，这使它们有可能在远低于低​​温下的额定电流的电流水平下运行。构建了GaN双脉冲测试（DPT）电路，并证明了GaN HEMT在低温下的工作电流几乎是额定电流的四倍。讨论和总结了在低温冷却条件下使用WBG设备的挑战。