GaAs/Ga0.47In0.53As lattice-mismatched Schottky barrier gates: Influence of misfit dislocations on reverse leakage currents

Abstract

Epitaxial GaAs has been grown on Ga0.47In0.53As by molecular beam epitaxy to form a lattice-mismatched Schottky barrier gate for field-effect transistor applications. The study of cross-sectional transmission electron microscopy shows that the misfit dislocations accommodating the 3.7% lattice mismatch between these two materials are confined in a GaAs interfacial layer of 300–400-Å thickness. As a result of significant reduction in dislocation densities, Schottky barrier gates made on a sample having a 960-Å-thick GaAs layer exhibit reverse leakage currents two orders of magnitude lower than those made on a sample with a 580-Å-thick GaAs layer. This approach looks promising for fabricating Ga0.47In0.53As field-effect transistors for optoelectronic integration as well as high-speed logic applications.