Electrical properties of molecular beam epitaxially grown $AlxGa1−xSbyAs1−y$ and its application in InP-based high electron mobility transistors

We have investigated the use of lattice-matched $AlxGa1−xSbAs$ quaternary alloys in InP-based microelectronic devices. The band alignment for $AlxGa1−xSbAs/InGaAs$ is calculated across the entire compositional range of x using van de Walle and Martin’s model solid theory, and the theoretical predictions agree with previously published values within 0.1–0.3 eV. Temperature-dependent current–voltage measurements are carried out on $Au/Cr/AlxGa1−xSbAs$ Schottky diodes grown by molecular beam epitaxy. From an Arrhenius analysis, an effective barrier height of 0.67–0.79 eV is obtained, which decreases as the x increases in the range of $0.5⩽x⩽0.9.$ For the first time, InAlAs/InGaAs high electron mobility transistors are fabricated with an $AlxGa1−xSbAs$ barrier enhancement layer. A reduced gate leakage and delay of gate forward turn-on are attributed to the incorporation of $AlxGa1−xSbAs.$ The effectiveness of $AlxGa1−xSbAs$ is more pronounced for $x=0.5$ and 0.7 than for $x=0.9.$