Deep-Level Transient Spectroscopy and Photoluminescence Studies of Formation and Depth Profiles of Copper Centers in Silicon Crystals Diffused with Dilute Copper

Abstract

We have observed the formation of the Cu centers in p-type Si crystals diffused with dilute Cu between 400 and 1000 °C by deep-level transient spectroscopy (DLTS) and photoluminescence methods. For the samples diffused below 800 °C, a DLTS Cu center denoted as the Cu DLB center was the main component and was almost uniformly distributed in the bulk. For the samples diffused above 800 °C, a precipitate-related Cu species was the main component at the surface, and low-concentration Cu DLB centers and another precipitate-related species were the main components in the bulk. We attributed the inhomogeneous depth profiles of the Cu species in the samples diffused above 800 °C to the out-diffusion of Cu atoms and their precipitation near the sample surface. The dissociation product of the Cu DLB center denoted as the Cu DLA center was occasionally produced by the diffusion of Cu below 600 °C due to the precipitation of interstitial Cu. On the basis of these observations, we discussed the formation kinetics and structures of the Cu DLB and Cu DLA centers.