Comparative Analysis of Recessed-Gate AlGaN/GaN HEMTs with GaN and β-Ga₂O₃ Buffer Layers

AlGaN/GaN High-Electron-Mobility Transistors are extensively employed in high-frequency and power applications as a result of their exceptional thermal stability and electron transport capacity. This investigation provides a simulation-based comparison of AlGaN/GaN HEMTs with GaN and β-Ga<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>O<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> buffer layers. The β-Ga<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>O<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> buffer’s ultra-wide bandgap characteristics have an impact on device performance, while the GaN buffer offers high electron mobility and excellent material compatibility. The recessed-gate structure, which consists of a β-Ga<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>O<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> buffer, improves transconductance, reduces gate-to-drain capacitance, and increases drain current density, thereby enhancing electrostatic control. Furthermore, β-Ga<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>O<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> functions as a natural back-barrier, which influences the confinement of two-dimensional electron gas (2DEG) and mitigates the effects of interface traps.The influence of the buffer layer on carrier transport and gate capacitance is examined through Sentaurus TCAD simulations, providing insights into its impact on device performance and electrostatic control. These results suggest that β-Ga<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>O<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> buffer layers have the potential to improve specific performance metrics in AlGaN/GaN HEMTs, offering them a promising alternative for next-generation power and RF applications.