Microwave power performance on AlGaN/GaN HEMTs on composite substrate

In this paper, microwave power performance at 10 GHz of HEMTs fabricated on MOCVD and MBE epitaxial structures grown on composite substrates is demonstrated. These substrates, based on monocrystalline-SiC layer on a polycrystalline-SiC (SiCopSiC), are engineered using the Smart Cuttrade technology. They are based on innovative engineering in which a thin SiC single crystal layer is transferred on top of a thick polycrystalline SiC wafer with a thin SiO₂ intermediary insulating layer. The process used for the devices fabrication on SiCopSiC is quite similar to those on SiC monocrystalline bulk developed previously. High power density was measured on both epi-materials at 10 GHz. Regarding the power results for the components based on MOCVD epi-material, the best value is an output power density of 5.06 W/mm associated to a PAE of 34.7% and a linear gain of 11.8 dB at V_DS = 30 V. In the frame of the MBE epilayer, the output power density is 3.58 W/mm with a maximum PAE of 25% and a linear gain around 15 dB at V_DS = 40 V.