MBE grown InAlAs/InGaAs lattice mismatched layers for HEMT application on GaAs substrate

Lattice mismatched high electron mobility transistors with InGaAs and InAlAs buffer layers have been grown by molecular beam epitaxy on GaAs substrate. Surface morphology of epilayers has been investigated using atomic force microscopy. An inverse step layer at the exit of the linear grade has been used to enhance relaxation of strain in heterostructures with indium contents ranging from 30% to 50% and impact of surface roughness on electrical properties has been investigated.