Investigation of Surge Current Capability of GaN E-HEMTs in The Third Quadrant: The Impact of P-GaN Contact

Gallium nitride (GaN) enhancement-mode high-electron-mobility transistors (E-HEMTs), featuring an inherently symmetric lateral channel, are highly favorable for both forward and reverse conduction in bidirectional DC/DC converter and DC/RF interconversion systems. Under the circumstances of current overshoot/oscillation, the GaN E-HEMTs would undergo a high surge current in the third quadrant which could possibly result in device failure. In this paper, the surge current capabilities of two types of commercial GaN E-HEMTs in the third quadrant are evaluated, whereby the impacts of different p-GaN technologies and gate-to-source voltage (V
_GS
) are revealed. The ohmic p-GaN contact and high V
_GS
, enabling higher efficiency of hole injection and channel modulation, can enhance the surge current capability of GaN E-HEMTs in the reverse conduction mode. To our best knowledge, it is the first time to investigate the surge current capability and to reveal the underlying mechanisms in lateral GaN power devices.