Whole wafer processing for the fabrication of opto-electronic devices provides significant advantages in terms of ease of handling and increased potential yield. However, it imposes a stringent demand on the development of non-destructive spatially resolved analytical methods to characterize substrates, epitaxial layers and devices. A photoluminescence system has been developed which allows rapid measurement of quantitative spectral information at a large number of spatial points. This allows the characterization of material quality and the development of systems for the deposition of higher quality and more highly uniform epitaxial layers. In this paper we will describe the SPM-200 photoluminescence system. This scanning stage system has the capability to quantitatively map wafers as large as 75 mm with a minimum sampling grid size of 2.5 μm. Photoluminescence signals from 450 to 2000 nm can be measured with the appropriate choice of detector and grating. Single element detectors and multi-element detector arrays can be used. The excitation can be software selected to be one of two premounted and prealigned lasers. The results of measurements on A1GaAs/GaAs and InGaAs(P)/InP epitaxial layers and GaAs substrates will be presented. Emphasis will be placed on the information that can be gained from not only spatial measurements at a single wavelength (topography) but also mapping of PL peak wavelength, intensity and full width half maximum. In addition to the room temperature measurements, low temperature (below 12 K) images of GaAs and other systems will be presented and discussed. © 1990.
