A superior cathodoluminescence spectral analysis and imaging system for semiconductor characterisation

Cathodoluminescence is a useful technique in the structural and electro optical characterisation of semiconductors. When performed in a electron microscope, both high spatial resolution images and spectra may be obtained by use of the correct equipment.Many designs for instruments suitable for cathodoluminescence spectral analysis and imaging in electron microscopes have been described in the literature during the past 25 years. These have often exhibited improved performance when compared with commercially available systems. The prime reason for this has been the willingness of the dedicated CL researcher to mount large, heavy monochromators directly to the chamber of their microscope. The result has been a microscope committed to CL analysis. However, many potential CL users have to use shared facilities and may not compromise the performance or appearance of the microscope. Subsequently, many CL systems have had the monochromator decoupled from the CL collection optics by either fibre optic bundles or quartz fibres. This has allowed the monochromator and its associated detectors to be easily decoupled from the SEM when not in use. Considerable transmission losses have been incurred and in many cases, it has been necessary to duplicate detectors to allow both spectral analysis and imaging. This has resulted in instruments which were less than optimum in both efficiency and operation.