SPATIALLY RESOLVED COMPOSITION MEASUREMENTS OF TERNARY EPITAXIAL LAYERS

Spatially resolved room temperature photoluminescence is a non-destructive optical characterisation technique which allows the measurement of relevant epitaxial layer properties over the whole wafer. In this work we describe application of spatially resolved and spectrally resolved photoluminescence mapping to determine the spatial variation of the composition of ternary epitaxial layers growth by MOCVD and MBE. We show results from device-quality epitaxial layers which are used for the manufacturing of optoelectronic devices. In particular we concentrate on InGaAs layers deposited on InP substrates and AlGaAs layers deposited on GaAs substrates. We discuss some of the suspected mechanisms for these variations and the use of the technique as a diagnostic aid for MOCVD and MBE growth.