InP is applied in high frequency technique, for lasers, communication technique and production of integrated circuits. Hence also for this material methods for defect investigation and quality control are needed.

Fig.1: Comparison of MD-PICTS spectra of as-grown Fe doped SI-InP samples from different crystal positions and thus different FE concentrations. The samples differ in their characteristic defect levels

MD-PICTS is a well suited method for the investigation of defect levels in InP. For example investigations on indium phosphide shows that the defect content changes during annealing processes, which may also have an impact on the distribution of electric properties. Whereas the defect content of as-grown samples depends on their position in the crystal, an equivalent set of defect levels is prominent in wafer-annealed samples. Figure 1 shows a comparison of Fe-doped SI-InP samples from different crystal positions. They differ in their characteristic defect levels. The observed peaks in FE-doped InP provided the first proof of iron acting as a recombination center in InP.