Electrostatic Engineering Using Extreme Permittivity Materials for Ultra-Wide Bandgap Semiconductor Transistors

The performance of ultra-wide bandgap semiconductors like
${\beta }$
-Ga
₂
O
₃
is critically dependent on achieving high average electric fields within the active region of the device. In this article, we show that dielectrics like BaTiO
₃
with extremely high dielectric constant can provide an efficient field management strategy by improving the uniformity of electric field profile within the gate–drain region of lateral field-effect transistors. Using this strategy, we achieved high average breakdown field of 1.5 and 4 MV/cm at gate–drain spacing (
${L}_{\text {gd}}$
) of 6 and
$0.5~{\mu }\text{m}$
, respectively in
${\beta }$
-Ga
₂
O
₃
, at a high channel sheet charge density of
$1.6\,\,{\times }\,\,10^{{13}}$
cm
⁻²
. The high channel charge density along with the high breakdown field enabled a record power figure of merit (
${V}_{\text {br}}^{{2}}/{R}_{\text {ON}}$
) of 376 MW/cm
²
at a gate–drain spacing of
${3}~{\mu }\text{m}$
.