TEM CHARACTERIZATION OF THE INTERFACE QUALITY OF MOVPE GROWN STRAINEDINGAAS GAAS HETEROSTRUCTURES/

In order to optimize the growth conditions of strained-layer InGaAs QW high-performance lasers by MOVPE, different growth parameters are sys tematically varied. These test structures as well as complete laser st ructures are carefully analysed. Special attention is given among othe rs to the homogeneity and interface quality of the quantum well. For ' 'thicker'' QW layers (>7 nm) - grown under standard conditions - it is possible to prove an increased smearing of the upper QW interface. Th is observation is in good correlation with AES measurements. For the f irst time, the inhomogeneous In distribution in the QW could be visual ized as a detectable segregation of In in the interface region by usin g high-resolution TEM techniques and new methods of image analysis.