【Domestic Papers】Characteristics of β-Ga₂O₃ MOSFETs on polycrystalline diamond via electrothermal modeling

      Researchers from the Harbin Institute of Technology have published a dissertation titled "Characteristics of β-Ga₂O₃ MOSFETs on polycrystalline diamond via electrothermal modeling " in Diamond and Related Materials.

Abstract

      The integration of polycrystalline diamond (PCD) has been considered as a promising approach for overcoming the thermal management challenges in β-Gallium oxide (β-Ga₂O₃) metal-oxide-semiconductor field effect transistors (MOSFETs). This study investigates the coupled electrical and thermal characteristics of β-Ga₂O₃-on-diamond MOSFETs via electrothermal modeling. Results reveal that thicker diamond improves heat transfer efficiency with an optimal value of ∼100 μm by utilizing regions with higher thermal conductivity. The ambient temperature (T_amb) correlates negatively with the device temperature rise (ΔT) due to reduced electrical mobility and current density at elevated temperatures. Excellent electrical performance has been demonstrated for β-Ga₂O₃ MOSFETs, with a high saturation current density (I_d,sat = 42.7 mA/mm) and a low specific on-resistance (R_ON,sp = 264.8 mΩ·mm²) at 300 K with V_g = −2 V and V_d = 20 V, along with a high on/off ratio (I_on/I_off ∼ 10¹¹) and a low subthreshold swing (SS = 83.3 mV/dec), making it highly suitable as a power switch. Comparative analysis with devices on other substrates (Si, SiC, and sapphire) highlights the exceptional carrier mobility and heat spreading capability benefited from the diamond substrate, especially at high power levels. Our TCAD-based fully-coupled electrothermal simulations provide comprehensive and accurate insights into the electrical and thermal performance of Ga₂O₃-based devices, offering guidance for the design and optimization of high-power devices.

Paper Link：https://doi.org/10.1016/j.diamond.2024.110847