Simulation of E-Mode β -Ga₂O₃ Interlayer-Based Vertical Trench Power MOSFET With Fast-Switching Performance at High Temperatures

In this paper, an interlayer-based vertical trench power <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula>-Ga2O3 MOSFET with nitrogen-doped current blocking layers (CBLs) is designed and simulated in Sentaurus TCAD. The proposed MOSFET achieves Enhancement-mode (E-mode) operation and better performance than the reported E-mode <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula>-Ga2O3 transistors with CBLs. The DC characteristics present a higher on/off current ratio of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{8}$ </tex-math></inline-formula> than the reported <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula>-Ga2O3 U-shaped MOSFETs, and a higher on-current density of 94 A/cm2, a lower specific on-resistance of 26.5 m<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Omega \cdot $ </tex-math></inline-formula>cm2, and a larger breakdown voltage of 483 V than the reported <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula>-Ga2O3 current aperture vertical MOSFETs. The thermal characteristic study shows that the proposed device can work up to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$500~^{\circ }$ </tex-math></inline-formula>C in E-mode operation with an on-current density of 35 A/cm2 and on-resistance of 104 m<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Omega $ </tex-math></inline-formula>.cm2. The dynamic characteristics are explored, and excellent switching performance with a turn-on time of 29 ns and a turn-off time of 48 ns at room temperature is achieved. At <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$500~^{\circ }$ </tex-math></inline-formula>C, the turn-on time slightly increases to 38 ns due to the reduced electron mobility, and the turn-off time is still in the order of 40 ns because of the less discharge time of the lower on-state gate charge. The proposed MOSFET is examined in a boost converter application, and an efficiency of 89% and a voltage conversion ratio of 1.42 for a duty cycle of 40% are obtained. Our work shows the proposed <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula>-Ga2O3 MOSFET has great potential as a high-speed switch in power electronics applications.