ON-Resistance Analysis of GaN Reverse-Conducting HEMT With Distributive Built-In SBD

Recently, a GaN reverse-conducting high-electron-mobility transistor (RC-HEMT) has been demonstrated. The RC-HEMT features built-in distributive Schottky contacts, which provide a low-loss freewheeling path. The RC-HEMT offers the same functionality as an HEMT/Schottky barrier diode (SBD) pair, but consumes much less chip area, thus its
${R}_{ \mathrm{\scriptscriptstyle ON}}$
(ON-resistance
$\times $
total device width) is significantly reduced. Theoretically,
${R}_{ \mathrm{\scriptscriptstyle ON}}$
of the RC-HEMT can approach that of an HEMT. In practice, due to certain geometry limitations,
${R}_{ \mathrm{\scriptscriptstyle ON}}$
of an RC-HEMT lies between an HEMT/SBD pair and a single HEMT. This work investigates the factors that influence
${R}_{ \mathrm{\scriptscriptstyle ON}}$
of the RC-HEMT using both experimental measurements and numerical simulations. It is found that
${R}_{ \mathrm{\scriptscriptstyle ON}}$
of the RC-HEMT is strongly affected by the geometry of the source and channel regions, where HEMT sections and SBD sections are interdigitally distributed. With coarse patterning of these regions,
${R}_{ \mathrm{\scriptscriptstyle ON}}$
of the RC-HEMT is close to the HEMT/SBD pair. Through proper geometry scaling,
${R}_{ \mathrm{\scriptscriptstyle ON}}$
of RC-HEMT is reduced and approaches that of HEMT.