Radio frequency analysis of scaled BaTiO3/Al2O3/In0.04Al0.70GaN0.26/GaN MISHEMTs

We demonstrate the effect of BaTiO3 integration on scaled BaTiO3/Al2O3/In0.04Al0.70GaN0.26/GaN metal–insulator–semiconductor high electron mobility transistors (MISHEMTs). We find that sputter processing and device fabrication decreases barrier thickness and mobility of the HEMT structure, and the inclusion of a GaN cap recovers the device performance. We then employ a 20-element lumped small signal equivalent circuit model to assess the impact of BaTiO3 integration on scaled devices. Finally, a demonstration of devices with various barrier and dielectric designs shows that BaTiO3 gate dielectric improves Vds and gate drive handling of devices, decreased the negative slope of the gain in the compression regime due to a more uniform field profile, and enables higher output power (Pout). It is shown that through the integration of BaTiO3 and a GaN cap, the output power of the devices increases from 1.42 W/mm to 5.77 W/mm.