AlGaN/GaN-HEMTs with a breakdown voltage higher than 100 V and maximum oscillation frequency fmax as high as 100 GHz

The N-Al0.27Ga0.73N/GaN High Electron Mobility Transistors (HEMTs) with different gate lengths Lg (ranging from 170 nm to 0.5 μm) and gate widths Ws (ranging from 100 to 1200 μm) have been studied. The S parameters have been measured; these parameters have been used to determine the current-gain cutoff frequency ft, the maximum oscillation frequency fmax, and the power gain MSG/MAG and Mason's coefficients were investigated in the frequency range from 10 MHz to 67 GHz in relation to the gate length and gate width. It was found that the frequencies ft and fmax attain their maximum values of ft = 48 GHz and fmax = 100 GHz at Lg = 170 nm and Wg = 100 μm. The optimum values of Wg and output power P out of the basic transistors have been determined for different frequencies of operation. It has also been demonstrated that the 170 nm Al0.27Ga0.73N/GaN HEMT technology provides both good frequency characteristics and high breakdown voltages and is very promising for high-frequency applications (up to 40 GHz).