Comparative analysis of electrical characteristic AlGaN/GaN HEMT on Si(111) and 4H-SiC for X-band high power application

Two different substrates of AlGaN/GaN HEMT have been employed and demonstrate the comparative analysis of improved DC and RF properties. Due to the characteristics of high power density, excellent thermal conductivity, 4H-SiC substrate has 18.9%, 10%, 8.6% higher values of drain current density, extrinsic transconductance and break down voltage than Si(111) substrates respectively. As a result, due to high drain current and thermal conductivity problem, Si substrate cannot overcome high power operation. In terms of output power SiC substrate has 8.6% higher than Si substrate in 2 × (200 × 0.5) μm² gate structure. Additionally, only SiC substrate which has 40 × (200 × 0.5) μm² gate structure can be operated at 31.6 W.