Phase Separation Suppression of MOVPE InxGa1-xN (x~0.4) Epitaxial Layer: A Detail Study and Estimation of Growth Conditions

Abstract

InxGa1-xN is one of the most advantageous materials for high performance electronic and optoelectronic devices.So a demanding analysis has been a central issue for the growth of InxGa1-xN to get it as better quality and phase separation free material. It is vital to determine the dependence of the quality and characteristics of epitaxial film on different growth parameters. For this effort, a model has been developed by using the thermodynamic and compositional analysis. The results obtained from this model has been compared and fitted with experimentally obtained data through XRD, RSM, PL, SEM etc. It has also been developed another model on the basis of previous model for growth rate concerning with ammonia flow rate, pressure in addition with different growth parameters. Both of these models are considered for InxGa1-xN film on GaN template with an In mole fraction up to 0.4 by Metal Organic Vapor Phase Epitaxy (MOVPE). To understand the effect of strain on phase separation it has been build up a relationship showing the dependence of strain on film thickness and In incorporation in the epitaxial film. To evaluate its perfectness, the result has been compared with the Matthews, Mader and Light Kinetic model for lattice relaxation. Finally three phase diagrams have been developed to optimize the various growth parameters in order to grow phase separation free material. The first phase diagram has been proposed to interpret the phase separation and In content evolution under the influence of growth temperature and precursor gas flow. The second phase diagram has been wished for choosing the value of growth rate to grow up better quality InGai-N material. The last one has been developed to include the critical thickness in binodal and spinodal decomposition curve of InxGa1-xN.