Electrostatic Engineering using Extreme Permittivity Materials for Ultra-wide Bandgap Semiconductor Transistors

TL;DR

This paper demonstrates that using high-k dielectric materials like BaTiO3 can significantly improve electric field management in ultra-wide bandgap semiconductor transistors, leading to record power performance.

Contribution

The study introduces a novel electrostatic engineering approach with extreme permittivity materials to enhance breakdown fields and power figures in beta-Ga2O3 transistors.

Findings

Achieved high breakdown fields of 1.5 MV/cm and 4 MV/cm at different gate-drain spacings.

Recorded a power figure of merit of 376 MW/cm^2 at 3 um gate-drain spacing.

Improved electric field uniformity using high-k dielectrics in ultra-wide bandgap transistors.

Abstract

The performance of ultra-wide band gap materials like $\beta$-Ga$_\mathrm{2}$O$_\mathrm{3}$ is critically dependent on achieving high average electric fields within the active region of the device. In this report, we show that high-k gate dielectrics like BaTiO$_\mathrm{3}$ can provide an efficient field management strategy by improving the uniformity of electric field profile in the gate-drain region of lateral field effect transistors. Using this strategy, we were able to achieve high average breakdown fields of 1.5 MV/cm and 4 MV/cm at gate-drain spacing (L$_\mathrm{gd}$) of 6 um and 0.6 um respectively in $\beta$-Ga$_\mathrm{2}$O$_\mathrm{3}$, at a high channel sheet charge density of 1.8x10$^\mathrm{13}$cm$^\mathrm{-2}$. The high sheet charge density together with high breakdown field enabled a record power figure of merit (V$^\mathrm{2}$$_\mathrm{br}$/R$_\mathrm{on}$) of 376 MW/cm$^\mathrm{2}$ at a gate-drain spacing of 3 um.