Abstract
The 100-nm T-gate InP-based InAlAs/InGaAs high electron mobility transistors (HEMTs) with the width of 2 × 50 μm and source-drain space of 2.4 μm are systematically investigated. High indium (In) composition of InGaAs layer was adopted to acquire the higher mobility of the channel layer. A sandwich structure was adopted to optimize the cap layers and produce a very low contact resistance. The fabricated devices exhibit extrinsic maximum transconductance Gm.max = 1441 mS/mm, cutoff frequency fT = 260 GHz, and maximum oscillation frequency fmax = 607 GHz. A semi-empirical model has been developed to precisely fit the low-frequency region of scattering parameters (S parameters) for InP-based HEMTs. Excellent agreement between measured and simulated S parameters demonstrates the validity of this approach.