InAlAs/InGaAs metamorphic high electron mobility transistors on GaAs substrate: Influence of indium content on material properties and device performance

The development of lattice mismatched InAlAs/InGaAs high electron mobility transistors on high-quality GaAs substrates (metamorphic HEMT) is of primary interest for millimeter-wave devices. These heterostructures grown on lattice mismatched substrates allow an extension of the composition range in the structures and to exploit enhanced properties, provided that the crystalline perfection of the layers as well as electrical quality are preserved. The aim of this work is to study the influence of indium mole fraction on material properties as well as its consequences on device performance.