InP-based enhancement-mode pseudomorphic HEMT with strained In0.45Al0.55As barrier and In0.75Ga0.25As channel layers

Using strained aluminum-rich In0.45Al0.55As as Schottky contact materials to enhance the barrier height and indium-rich In0.75Ga0.25As as channel material to enhance the channel performance, we have developed InP-based enhancement-mode pseudomorphic InAlAs/InGaAs high electron mobility transistors (E-PHEMT's) with threshold voltage of about 170 me A maximum extrinsic transconductance of 675 mS/mm and output conductance of 15 mS/mm are measured respectively in room temperature for I Irm-gate-length devices, with an associated maximum drain current density of 420 mA/mm at gate voltage of 0.9 V. The devices also show excellent rf performance with cutoff frequency of 55 GHz and maximum oscillation frequency of 62 GHz, To the best of the author's knowledge, this is the first time that InP-based E-PHEMT's with strained InAlAs barrier layer were demonstrated.