Use of Rutherford backscattering and optical spectroscopy to study boron implantation in cadmium telluride

The effect of large dose boron implantation in single crystal cadmium telluride (CdTe) has been investigated by Rutherford backscattering spectrometry (RBS), with channeling double crystal X-ray diffraction (DCD), and photoreflectance (PR) spectroscopy. Comparisons are made with the results of identical B implantations of Silicon and Gallium Arsenides crystals. Multiple energy implantations were performed at room temperature and liquid nitrogen temperature with total doses up to 1.5 x 10 to the 16th B+ ions/sq. cm. The implanted B distribution was measured with neutron depth profiling (NDP) and found to agree well with Monte Carlo ion range calculations. The RBS results showed that the CdTe crystals had not been rendered completely amorphous even for the highest dose implantation unlike GaAs and Si. Furthermore, the DCD results showed little implantation-induced structure in the rocking curves from the implanted CdTe crystals, in contrast to GaAs. The consequences of annealing at 500 C in an attempt to regrow the crystal structure are also discussed.