Non-linear surface reaction kinetics in GaAs selective area MOVPE

Abstract

Two-dimensional numerical simulation on growth rate non-uniformity of selective area growth (SAG) in metal-organic vapor phase epitaxy (MOVPE) is an effective method to examine the surface reaction kinetics, which is difficult to be investigated in mass-transport limited growth regime. Non-linear kinetic analysis based on the Langmuir–Hinshelwood mechanism is revealing the intrinsic process in MOVPE. Two important kinetic parameters, surface reaction rate constant ( k s n) and adsorption equilibrium coefficient ( K), were successfully extracted from GaAs SAG–MOVPE on (1 0 0) exact and 2° off misoriented substrates in the temperature range of 520–600 °C. The activation energy is 126–127 kJ/mol for k s n, and −53 to −59 kJ/mol for K. The surface coverage of Ga-species during the GaAs growth can be estimated from these kinetic parameters as 0.05–0.60. There is a critical temperature ( T c) for the conversion of GaAs surface reaction mode. When growth temperature is higher than T c, non-linear kinetic can be simplified as linear kinetic mode which is easier in calculation. T c was found to be 600 °C for (1 0 0) exact GaAs substrate and 650 °C for 2° off substrate.