L g = 25 nm InGaAs/InAlAs high-electron mobility transistors with both f T and f max in excess of 700 GHz

In this paper, we report an L g = 25 nm InGaAs/InAlAs HEMT on InP substrate that delivers excellent high-frequency characteristics. The device exhibited a value of maximum transconductance (g m_max) = 2.8 mS μm−1 at V DS = 0.8 V and on-resistance (R ON) = 279 Ω μm. At I D = 0.56 mA μm−1 and V DS = 0.5 V, the same device displayed an excellent combination of f T = 703 GHz and f max = 820 GHz. To the best of the authors' knowledge, this is the first demonstration of a transistor with both f T and f max over 700 GHz on any material system.