Micro-Raman for compositions characterization of selective area growth of AlxGayIn1-x-yAs materials by metal-organic vapor-phase epitaxy

Micro-Raman scattering measurements were used to study the phonon modes and to analyze the local variation of composition and strain in the micron range of AlxGayIn1-x-yAs materials grown in the regime of selective area growth (SAG) at low-pressure metal-organic vapor-phase epitaxy (LP-MOVPE). For the planar AlxGayIn1-xyAs layers, the indium composition is almost constant at around 0.53 while the aluminum content covered the composition range from 0 to 0.47. The Raman spectra were recorded with a confocal micro-Raman spectrometer. Raman cartography at a lateral resolution of 1 pm was performed to Study the spatial variation of the phonon peaks characteristics in the SAG GayIn1-yAs and AlxGayIn1-x-yAs materials. The three main Al(x)Ga(y)In1(-x-y)As phonon modes were analyzed: the InAs-like, GaAs-like and AlAs-like LO modes. These modes characteristics depend strongly on composition, strain and position inside the mask aperture for the SAG materials, and this dependence gives the ability to analyze the local composition and strain variations in these systems, which is very important in order to understand the influence of MOVPE growth parameters on composition and strain and to optimize the SAG growth conditions. (C) 2008 Elsevier B.V. All rights reserved.