Thermal behavior of AlGaN/GaN HEMT on silicon Microstrip technology

High-resistivity Silicon substrates, thanks to their low cost and large wafer diameter, could represent a viable solution for the high power GaN-based transistors realization, even if device thermal management optimization is necessary because of thermal conductivity limitations of Silicon. In this work, a comparison between L_G=0.5μm GaN on Silicon HEMT devices fabricated in Coplanar Waveguide (CPW) and Microstrip (MS) technology will be presented, showing the main differences in DC, pulsed and RF power performances related to the thermal behavior. In particular we will demonstrate that Silicon substrate thickness reduction down to 50μm results in negligible change in Power Density and PAE (>;3.5 W/mm and >;45% @ V_DS=25 V respectively) for duty factor ranging from 1% to 50%.