Superconducting transition-edge microcalorimeters for X-ray microanalysis

We have developed high-performance X-ray microcalorimeters based on superconducting transition-edge sensors. These superconducting detectors, which are cooled by a compact adiabatic demagnetization refrigerator mounted on a scanning electron microscope, provide significant new capabilities for X-ray microanalysis. The performance characteristics of these detectors are nearly ideal for many applications in X-ray microanalysis, attaining an energy resolution of 3-4 eV at a counting rate of 500 s/sup -/ and an effective collection area of 4 mm/sup 2/. The excellent energy resolution enables measurements of chemical shifts in X-ray spectra caused by changes in electron binding energy due to chemical bonding. Another important application of these detectors is analysis of contaminant particles and defects for the semiconductor industry. We present data demonstrating the analysis of particles on Si wafers, including 0.3 /spl mu/m tungsten particles and 0.1 /spl mu/m alumina particles.