An innovative approach for controlled epitaxial growth of GaAs in real MOCVD reactor environment

Abstract

In present paper, the off-lattice homoepitaxy of GaAs over (100) GaAs substrate crystal is reported. The innovative inhouse developed numerical technique exploiting atomic scale kinetic Monte Carlo algorithms for simulation of thin film deposition is used to replicate the MOCVD reactor based epi-growth with appropriate reactor's input conditions. The epi-growth mechanism includes adsorption, diffusion and desorption processes depending upon different energies. The lattice parameter, roughness and strain of epi-grown layer have been extracted and energy-wave vector (E-k) dispersion relation has been simulated with empirical pseudopotential method using lattice constant extracted from epi-grown film. The results obtained on the basis of proposed simulation has been compared and contrasted against experimental results. The study of growth rates at different partial pressure of TMG precursor and at fixed partial pressure of TBAs precursor depicts the linear growth rate. The slope of epi-growth rates has been obtained 5.78 with respect to partial pressure. The curve for roughness shows linear increase initially which later flattens and becomes almost constant. Low values of strain extracted for initial layers because of some randomness prevalent in KMC. The energy band gap value of epi-grown GaAs thin film over GaAs is extracted 1.44eV.