Metalorganic vapor-phase epitaxially grown n-type GaAs/InGaP/GaAs structures with different GaAs cap layer thicknesses were studied by deep-level transient spectroscopy. An electron trap E1 with a thermal activation energy of 0.75eV was formed in lattice-matched InGaP after metalorganic vapor-phase epitaxial growth, if was not capped by sufficiently thick GaAs. The lattice mismatch of the InGaP layer influences the thermal activation energy of the deep defect, but not its occurrence or concentration. The starting surface concentration of the deep level defect as well as its diffusion at room temperature into the InGaP were apparently promoted by intrinsic defects in the InGaP layer determined by its growth condition. The shape of the depth profiles suggested that an extrinsic defect moves via interstitial sites into empty substitutional sites of the InGaP lattice. Oxygen atoms on P sites were probable candidates for the E1-related defects.

Defect Study of MOVPE-Grown InGaP Layers on GaAs. A.Knauer, P.Krispin, V.R.Balakrishnan, M.Weyers: Journal of Crystal Growth, 2004, 272[1-4], 627-32