Beta-gallium oxide (β-Ga2O3) is an emerging ultra-wide bandgap semiconductor material for high-power devices. However, one of the major drawbacks is the low thermal conductivity resulting in poor heat dissipation, and the so-called self-heating effect reduces carrier mobility and drain current degradation, and even causes a device reliability issue. Here, we propose a bottom-gate β-Ga2O3 field-effect transistor with a hexagonal boron-nitride (h-BN) gate-insulator and investigate the self-heating effect in comparison with an aluminum oxide (Al2O3) insulator using physics-based TCAD simulations. The h-BN with high thermal conductivity reduces the lattice temperature of the β-Ga2O3 channel and decreases drain current degradation. Furthermore, as the thickness of the insulator decreases below 50 nm and the channel length is scaled down to 5 μm, the reduced self-heating effect becomes more prominent. The results imply that the highly thermal-conductive h-BN insulator is promising for achieving high performance β-Ga2O3 metal insulator semiconductor field-effect transistor (MISFET) with the bottom-gate configuration.
This work was funded and conducted under the Competency Development Program for Industry Specialists of the Korean Ministry of Trade, Industry and Energy (MOTIE), operated by Korea Institute for Advancement of Technology (KIAT) (No. N0001883, HRD program for Software-SoC convergence).
