Paralleling of Gallium Nitride Power Semiconductor Devices: A Review and Future Perspectives

Wide-bandgap (WBG) semiconductors are propelling a paradigm shift in advanced power electronics, offering functionality that includes higher-switching-frequency operation with improved efficiency and power density possibilities. Gallium nitride (GaN) exhibits unique material properties that correspond to device parameters beneficial for achieving an improved performance compared to its counterparts. The inception of GaN power semiconductor devices has enabled advanced power electronics to realize efficient and compact power converters. However, the current rating of the devices is constrained, and paralleling of the devices is vital to realize high-currentrated power modules. Furthermore, paralleling of the devices can provide improved cooling results in high-power-density systems. This paper presents a comprehensive review study of the paralleling of GaN devices to discuss the different challenges associated with paralleling. One of the fundamental challenges is associated with the design of a structure for paralleling GaN devices. The parallel device structure consequently impacts the parasitics of the device, which limit the operating switching frequency and thermo-mechanical aspects. Furthermore, power loop inductance, gate loop inductance asymmetry, common-source inductance, gate inductance trace length mismatch, and different challenges lead to design trade-offs and efforts to optimize the design by realizing an appropriate trade-off, considering low-inductance packaging along with thermal strategies, and considering a parallel circuit layout and structure. Considering the recent research trends and studies related to the design of parallel GaN devices, this paper presents future perspectives anticipating the realization of an improved parallel GaN device structure.