ABSTRACT
We report in this paper the design, fabrication, and DC/RF performance of a new record for InGaAs/InP doped channel heterojunction FET's (DC-HFET's) with a strained Ga0.2In0.8P Schottky Barrier enhancement Layer (SBEL). The 0.25 μm gate-length devices show excellent RF performance, with a unity current-gain cutoff frequency (ft) of 117 GFIz and a maximum frequency of oscillation (fmax) of 168 GHz. These values are comparable to those of InGaAs channel high electron mobility transistors (HEMT's) with the same gate length which suggest that the speed of the device is dependent upon the high field electron velocity which is related to the energy separation between the T-L separation, ΔTL, and the electron effective mass rather than high electron mobility. To the best of the author's knowledge, this is the highest reported fT for In0.53Ga0.47As/InP DCHFET's with a strained Ga0.2In0.8P SBEL.
