A Comparison of the Structural Quality of High-In Content InGaAsN Films Grown on InGaAs Pseudosubstrate and on GaAs Substrate

Abstract

The use of an InGaAs buffer layer was applied to the growth of thick InxGa1-xAs1-yNy layers with higher In contents (x > 30%). In order to obtain the lattice-matched InGaAsN layer having the bandgap of 1.0 eV, the In0.2Ga0.8As was chosen. In this work, the In0.3Ga0.7As0.98N0.02 layers were successfully grown on closely lattice-matched In0.2Ga0.8As buffer layers (InGaAsN/InGaAs). Structural quality of such layers is discussed in comparison with those of the In0.3Ga0.7As0.98N0.02 layers grown directly on the GaAs substrate (InGaAsN/GaAs). Based on the results of transmission electron microscopy, the misfit dislocations (MDs), which are located near the InGaAsN/GaAs heteroepitaxial interface, are visible by their strain contrast. On the other hand, no generation of the MDs is evidenced in the InGaAsN layer grown on the In0.2Ga0.8As pseudosubstrate. Our results demonstrate that a reduction of misfit strain though the use of the pseudosubstrate made possible the growth of high In-content InGaAsN layers with higher crystal quality to extend the wavelength of InGaAsN material.