High-performance AlGaN/GaN HEMTs on silicon substrates

In this work the performance of AlGaN/GaN HEMTs on silicon substrates is presented. Prepared devices exhibit a saturation current of 0.91 A/mm and sustain significantly higher DC power in comparison to devices on sapphire. Markedly lower reduction of I/sub DSs/ and g/sub m,ext/ with increased temperature due to better thermal conductivity of silicon is shown. A unity gain cutoff frequency f/sub T/ of 32 and 20 GHz and a maximum frequency of oscillation of 27 and 22 GHz are obtained for devices with gate lengths of 0.7 and 0.5 /spl mu/m, respectively. These are the highest values reported so far on AlGaN/GaN/Si HEMTs. Presented values are comparable to those known for devices on sapphire and SiC substrates.