Concentration Study of Deep-Level Cu Center in Cu-Diffused Si Crystals by Deep-Level Transient Spectroscopy and Photoluminescence Measurements

Abstract

The concentration of the Cu center, located at Ev + 0.1 eV (Ev: top energy of the valence band) in p-type silicon crystals diffused with Cu of various concentrations at 700°C, was measured by deep-level transient spectroscopy (DLTS). The DLTS concentration of the center was almost linearly dependent on the concentration of dissolved Cu over a wide range and the average concentration ratio of the center was about 2%. From the linear relationship between the intensity of the 1.014 eV photoluminescence Cu center and the concentration of the DLTS center, the identities of both centers were assumed. The comparison of the maximum concentration of the Cu center observed in the present study (∼1013 cm-3) with reported solubility of substitutional Cu (Cus) (<1010 cm-3) showed that the model containing Cus such as Cus–Cui (i: interstitial) was not appropriate for the center.