Compositional Transformation between Cu Centers by Annealing in Cu-Diffused Silicon Crystals Studied with Deep-Level Transient Spectroscopy and Photoluminescence

Abstract

The annealing behavior of Cu centers in Si crystals diffused with Cu at 700 °C has been observed. The center having an energy level at Ev + 0.07 eV (Ev: top energy of the valence band), denoted as the CuDLB center, showed the dominant component of the as-diffused samples. Two alternative species [denoted as the CuDLA and H(85) centers] were observed by annealing the samples between room temperature and 600 °C. By annealing the samples at 600 °C and above, these alternative centers completely disappeared and the concentration of the CuDLB center almost recovered. From the analysis of the data we drew the following conclusions: The three centers are analogs containing the same core. The CuDLA center is a dissociation product of the CuDLB center; the core of the CuDLA center itself contains one Cu atom. The CuDLB center has a structure consisting of the CuDLA center and three Cui atoms forming weak bonds around the CuDLA center. The H(85) center is an intermediate species between the CuDLA and CuDLB centers.