Sub-Threshold Characteristics of Laterlly Gated AlGaAs/InGaAs pHEMT Fabricated with Focused Ion Beam Implantation
W. F. Tseng, David H. Monk
We have used a focused ion beam (FIB) technique to fabricate laterally gated AlGaAs/InGaAs pseudomorphic high electron mobility transistors (pHEMTs), and have characterized them electrically. The FIB direct-write defines the current path. An ion dose of 12 x 1014 ions/cm2 from a 25 keV Ga+ beam gives satisfactory electrical isolation. The fabricated transistors show typical field-effect transistor (FET) characteristics. For a properly adjusted n-AlGaAs layer, transfer characteristics (Ids vs. Vg) in the sub-threshold region show gate leakage similar to that of metal-semiconductor FETs. For the thicker n-AlGaAs layer, the sub-threshold transfer characteristic shows additional conduction with sporadic current-spikes. We attribute the cause of sporadic current-spikes to deep donors or DX centers in the silicon-doped AlGaAs layer.
deep donor, DX center, focused ion beam (FIB), pseudomorphic high electron, mobility transistor (pHEMT)
and Monk, D.
Sub-Threshold Characteristics of Laterlly Gated AlGaAs/InGaAs pHEMT Fabricated with Focused Ion Beam Implantation, Materials Letters
(Accessed December 5, 2023)