High performance metamorphic In_0.32Al_0.68As/In_0.33Ga_0.67 As HEMTs on GaAs substrate with an inverse step InAlAs metamorphic buffer

摘要

Summary form only given. Recently, InAlAs-InGaAs high electron mobility transistors lattice mismatched on GaAs substrates (metamorphic HEMTs) have been subject to a great deal of interest and development. Metamorphic structures using a graded buffer offer an arbitrary choice of lattice constant and indium composition. Here, we present the successful realization of a high performance metamorphic In_0.32 Al_0.68As-In_0.33Ga_0.67As HEMT grown on GaAs. This structure presents several advantages over the pseudomorphic HEMT. The high ΔE_c of 0.7 eV leads to a high sheet carrier density and good confinement; in addition, unstrained materials have a higher electron velocity, and the high band gap of In _0.32Al_0.68As gives a better Schottky barrier height. Metamorphic In_0.32Al_0.68As-In_0.33 Ga_0.67As HEMT layers were grown by solid source molecular beam epitaxy on two-inch (100) GaAs substrates. The results for the devices produced demonstrate the processability and feasibility of high performance In_0.32Al_0.68As-In_0.33 Ga_0.67As-GaAs HEMTs using an inverse step metamorphic buffer with low cross hatch