10-kV Lateral β-Ga₂O₃ MESFETs With B Ion Implanted Planar Isolation

In the letter, high performance lateral
$\beta $
-Ga
₂
O
₃
metal -semiconductor field effect transistors (MESFETs) with ultra-high breakdown voltage (
${V}_{\textit {br}}{)}$
over 10 kV are demonstrated. Planar isolation is realized by B ion implantation to avoid the ragged mesa edge and damage induced by traditional dry etching. A T-shaped gate and source field plate (FP) were adopted to suppress the peak electric field in both Ga
₂
O
₃
channel and SiN
_x
passivation layer. The planar isolated MESFETs with source-drain length of
$103~\mu \text{m}$
that use an
i
n-situ unintentionally doped (UID) Ga
₂
O
₃
cap layer as a gate dielectric showed a maximum destructive breakdown voltage of greater than 10 kV, combined with the specific on-resistance (
${R}_{\textit {on},\textit {sp}}{)}$
of 2922
$\text{m}\Omega \cdot $
cm
²
, a power figure of merit (
P
FOM) more than 34.2 MW/cm
²
is obtained. The results suggest that the B ion implanted isolation and device structure used in this work improve the performance of lateral
$\beta $
-Ga
₂
O
₃
MESFETs.