Large Area 1.2 kV GaN Vertical Power FinFETs with a Record Switching Figure-of-Merit

Abstract

This letter presents the first experimental study on capacitances, charges, and power-switching figure of merits (FOM) for a large-area vertical GaN power transistor. A 1.2-kV, 5-A GaN vertical power FinFET was demonstrated in a chip area of 0.45 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , with a specific on-resistance of 2.1 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{m}\Omega \cdot \textsf {cm}^{\textsf {2}}$ </tex-math></inline-formula> and a threshold voltage of 1.3 V. Device junction capacitances were characterized and their main components were identified. This was used to calculate the switching charges and practical switching frequencies. Device FOMs were then derived that take into account the trade-offs between the conduction and switching power losses. Our GaN vertical FinFETs exhibit high-frequency (~MHz) switching capabilities and superior switching FOMs when compared with commercial 0.9-1.2-kV Si and SiC power transistors. This letter shows the great potential of GaN vertical FinFETs for next-generation medium-voltage power electronics.