Monolithic Bidirectional GaN-on-GaN Vertical Transistor Technologies: Exploring Bidirectional CAVET for Next-Generation Switching Applications with Symmetrical Power Control

In this study, we designed and experimentally demonstrated a monolithic-integrated bidirectional GaN-on-GaN trench current aperture vertical electron transistor (BD-CAVET), capable of current conduction and voltage blocking in both directions. The trench CAVET was grown on a GaN substrate and incorporated a highly conductive 2D electron gas (2DEG) channel with a peak field effect mobility (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${\mu}$</tex-math></inline-formula><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">FE</sub>) of 1,792 cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>/(V·s). The BD-CAVET exhibited symmetrical <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">I–V</i> characteristics in bidirectional mode, achieving a specific on-resistance (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</i><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on,sp</sub>) of 2.5 mΩ·cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and a breakdown voltage of 200 V in both the first and third quadrants. In single-directional mode, the BD-CAVET conducted current in one direction with a turn-on offset voltage of 1 V. Reverse conduction of the fabricated trench CAVET was also investigated, revealing that the primary path for reverse current flow was through the 2DEG channel.