High electron mobility AlInSb/InAsSb heterostructures grown on GaAs substrates by molecular beam epitaxy

We have designed and fabricated high-electron-mobility heterostructures, for use in high-speed transistors and magnetic field sensors, which use InAs _y Sb_{1- y} group-V alloys as a channel material. The electron mobility in an InAs _y Sb_{1- y} channel that is only 20 to 30 nm thick and is sandwiched between Al_0.15 In_0.85Sb high-resistivity barrier layers, was improved to 28,000 cm²V^-1s^-1 at room temperature by reducing the lattice-mismatch between the channel and barrier layers. This mobility is an order of magnitude greater than that of the highly strained Al_0.15In_0.85Sb/InSb/A1_0.15In_0.85Sb heterostructure grown as a reference. The group-V alloys were formed by modulating As₂ and Sb₂ beams during growth. The sheet resistance of 1.1-pm-thick AlJni,,Sb layers exceeded 50 kΩ/sq. at an A1 content of 0.15.