A comprehensive diagram to grow (0001)InGaN alloys by molecular beam epitaxy

The composition, strain and surface morphology of (0001)InGaN layers are investigated as a function of growth temperature (460–645 °C) and impinging In flux. Three different growth regimes: nitrogen-rich, metal-rich and intermediate metal-rich, are clearly identified and found to be in correlation with surface morphology and strain relaxation. Best epilayers’ quality is obtained when growing under intermediate metal-rich conditions, with 1–2 monolayers thick In ad-coverage. For a given In flux, the In incorporation decreases with increasing growth temperature due to InN thermal decomposition that follows an Arrhenius behavior with 1.84±0.12 eV activation energy.

► Study of In incorporation as functions of growth temperature and impinging In flux.
► InGaN surface morphology strongly correlated to the growth regime.
► InGaN growth diagram constructed. Growth regimes’ borders analytically determined.
► InGaN epilayer relaxation rate dependent on growth regime.
► Difference in In incorporation into InAlN and InGaN explained by their decomposition parameters.