Effects of Structural Variation for Improved Performance of a Vertical AlGaN/GaN Superjunction HEMT

A GaN-based vertical superjunction high electron mobility transistor (HEMT) is analyzed theoretically to improve specific on-resistance $(\mathrm{R}_{\text{on}})$ and breakdown voltage (BV). The Drain is vertically aligned with the Source and Gate in a vertical superjunction HEMT, where the width is divided into two pillars, p and n. Each of these pillars is referred to as a half pillar. The devices are simulated with a particular doping concentration of $2.76\times 10^{16}\mathrm{cm}^{-3}$ for p-pillar and $1\times 10^{16} \mathrm{cm}^{-3}$ for the n-pillar. With the decrease of half-pillar width and epi-layer thickness $(\mathrm{T}_{\mathrm{epi}}),\mathrm{R}_{\mathrm{on}}$ decreased, while with the increase of half-pillar width and epi-layer thickness, BV increased. The $\mathrm{R}_{\text{on}}$ was reduced to $4.67\mathrm{m}\Omega.\mathrm{cm}^{2}$ with a BV of 5050 V using the optimized design. These findings imply that the optimized structure of vertical superjunction HEMT contributes to better $\mathrm{R}_{\text{on}}$ and BV