Low Turn-On Voltage and High Breakdown Voltage β-Ga2O3 Diode With Fin Channel and Ohmic Contact Anode

In this work, a low turn-on voltage (
${V}_{{ \mathrm{\scriptscriptstyle ON}}}$
) and high breakdown voltage (BV) beta-phase gallium oxide (
$\beta $
-Ga2O3) diode with a Fin channel combined with an ohmic contact anode and composite field-plate (FOCF) is proposed. Its electrical characteristics are investigated by Sentaurus TCAD simulation. The novel FOCF diode has two features: one is a Fin channel combined with ohmic contact anode (FO) to achieve metal–insulator–semiconductor (MIS)-like forward/reverse characteristics and thus realize a very low
${V}_{{ \mathrm{\scriptscriptstyle ON}}}$
; the other is composite field-plate (CF) to improve BV, consisting of Al2O3 and SiN
$_{X}$
dual-dielectric layers to form step-shaped field plate. When the forward voltage (
${V}_{{\text {F}}}$
) is 0 V, the Fin channel is pinched off due to the work function difference between the anode metal and
$\beta $
-Ga2O3; thus, the pinch-off effect allows the ohmic contact anode to take place of Schottky contact anode to significantly reduce
${V}_{{ \mathrm{\scriptscriptstyle ON}}}$
. As
${V}_{{\text {F}}}$
increases, the electron accumulation layers can be formed along the Fin sidewalls to improve current capability and reduce ON-resistance. Moreover, the pinch-off effect suppresses reverse leakage current and CF modulates the electric field distribution, both of which improve BV. The proposed FOCF
$\beta $
-Ga2O3 diode achieves low
${V}_{{ \mathrm{\scriptscriptstyle ON}}} =0.45$
V, high BV
$=$
2204 V, and Baliga’s figure of merit (BFOM) up to 1.47 GW/cm2. Therefore, the proposed structure provides a new design concept and enhances the application potential for high-power and low-loss
$\beta $
-Ga2O3 diodes.