Gallium nitride (GaN) power devices are employed in an increasing number of applications thanks to their excellent performance. Nevertheless, their potential for cryogenic applications, such as space, aviation, and superconducting systems, has not yet been fully explored. In particular, little is known on the device performance below liquid nitrogen temperature (77 K) and the behavior of popular GaN architectures such as gate injection transistor and Cascode below room temperature has not yet been reported. Most importantly, it is still unclear how the different device loss contributions, i.e., conduction, soft- and hard-switching losses, change at cryogenic temperatures. In this letter, we investigate and compare the performance of four GaN commercial power devices in a wide temperature range between 400 and 4.2 K. All of the tested devices can successfully operate at cryogenic temperatures with an overall performance improvement. However, different GaN HEMT technologies lead to significant variations in device gate control and loss mechanisms, which are discussed based on the device structure. The presented results prove the promising potential of the GaN technology for low-temperature applications and provide precious insights to properly design power systems operating under cryogenic temperatures and maximize their efficiency.

中文翻译：

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氮化镓功率器件的低温应用性能可低至4.2 K

氮化镓（GaN）功率器件由于其出色的性能而在越来越多的应用中得到使用。然而，它们在诸如太空，航空和超导系统等低温应用中的潜力尚未得到充分开发。特别是，在液氮温度（77 K）以下，器件性能知之甚少，尚未报道流行的GaN体系结构（例如，栅极注入晶体管和Cascode在室温以下）的性能。最重要的是，仍不清楚在低温下不同的器件损耗贡献（即，传导损耗，软开关损耗和硬开关损耗）如何变化。在这封信中，我们研究并比较了四种GaN商用功率器件在400至4.2 K的宽温度范围内的性能。所有经过测试的设备都可以在低温下成功运行，并且总体性能得到改善。但是，不同的GaN HEMT技术会导致器件栅极控制和损耗机制发生重大变化，这将根据器件结构进行讨论。提出的结果证明了GaN技术在低温应用中的潜在潜力，并为正确设计在低温温度下运行的电源系统并最大化其效率提供了宝贵的见识。