Simulation Study of a p-GaN HEMT With an Integrated Schottky Barrier Diode

In this article, a novel
${p}$
-GaN high-electron-mobility transistor (HEMT) with a built-in Schottky barrier diode (SBD) is proposed and investigated by TCAD simulation. The anode contact of the integrated SBD is isolated from the ohmic contact of the source electrode by a
${p}$
-GaN isolation region. The cathode of the SBD is connected to the drain electrode. In the proposed Schottky barrier diode/HEMT (SB-HEMT), a channel under the
${p}$
-GaN isolation region is turned on during forward conduction to further reduce the specific ON-resistance (
${R}_{ {\text{ON}},\text {sp}}$
). With a minimum sacrifice on
${R}_{ {\text{ON}},\text {sp}}$
, the reverse ON-state voltage,
${V}_{\text {R}- {\text{ON}}}$
(at a current density of 50 mA/mm), for the SB-HEMT is reduced by 33% (from 2.43 to 1.62 V) when compared with a conventional HEMT (C-HEMT). Compared with the C-HEMT with a separate on-chip SBD (C-HEMT/SBD), the SB-HEMT shows much better trade-off between
${V}_{\text {R}- {\text{ON}}}$
and
${R}_{ {\text{ON}},\text {sp}}$
. The total switching loss (
${E}_{\text {total}}$
) of the proposed SB-HEMT with resistive load is lower than that of the C-HEMT and is reduced by up to 21% when compared with that of the C-HEMT/SBD with different area ratio between the HEMT and SBD regions.