高频

This article reports on the performances of a high-electron-mobility transistor (HEMT) with Al0.62Ga0.38N channel layer and Al0.84Ga0.16N barrier layer grown by metalorganic chemical vapor deposition (MOCVD). The device in this report demonstrated a contact resistance ( R_C ) of 3.7~ mm and a sheet resistance ( R_ sh ) of ~3.3 k /sq. For a device with 180-nm gate length and 3- m source-to-drain length, excellent electrical characteristics have been achieved with a high f_ T of 30.5 GHz and f_ of 55.3 GHz. The device also exhibited high drain current (0.46 A/mm) while maintaining low gate and drain leakage. A high breakdown voltage (up to 315 V) was also obtained, indicating excellent high-power capabilities with a high Johnson’s figure of merit (JFOM) of 9.6 THz V. This JFOM value is the highest among other ultra wide bandgap (UWBG) transistors. In this report, the barrier design of the devices is further discussed to obtain a better understanding of relationships between the barrier thickness and high-frequency performances. Furthermore, the intrinsic electron velocity is extracted from the small-signal parameters to be 1 10^7 cm/s using the drain delay method, demonstrating good carrier transport properties.