Low On-Resistance High-Breakdown Normally Off AlN/GaN/AlGaN DHFET on Si Substrate

Ultrathin-barrier normally off AlN/GaN/AlGaN double-heterostructure field-effect transistors using an in situ SiN cap layer have been fabricated on 100-mm Si substrates for the first time. The high 2DEG density in combination with an extremely thin barrier layer leads to enhancement-mode devices with state-of-the-art combination of specific on-resistance that is as low as 1.25 $\hbox{m}\Omega\cdot\hbox{cm}^{2}$ and breakdown voltage of 580 V at ${V}_{\rm GS} = \hbox{0}\ \hbox{V}$ . Despite the 2-$\mu\hbox{m}$ gate length used, the transconductance peaks above 300 mS/mm. Furthermore, pulsed measurements show that the devices are dispersion free up to high drain voltage ${V}_{\rm DS} = \hbox{50}\ \hbox{V}$. More than 200 devices have been characterized in order to confirm the reproducibility of the results.