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

Abstract

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.