Materials Design for Cu Gettering by Electronic Dopants in Silicon

Abstract

In the silicon device process, there is a strong demand for eliminating copper contamination. Gettering of Cu by dopant atoms is a useful method for this purpose. In this paper, the gettering of Cu is theoretically studied. We have assessed the efficiency of gettering through the evaluation of the binding energies between Cu and electronic dopants and the dissociation energies. The calculated dissociation energies well describe the efficiency of various dopants, which have been found experimentally. It is shown that B and Al are the most efficient gettering centers among single dopants. The present study provides the basis for further study of the gettering mechanism and for the design of efficient gettering centers.

An Investigation of Material Design for Gettering

“…The atom configurations and binding energy E b between Cu and complexes are shown in Fig 1. 0.04 2.10 0.69 [5], and those of O with Cu (0.16eV) [3].Furthermore, we found that the binding energy of BO complexes with Cu are higher with increasing oxygen atoms. Figure 1 shows the stable atom configuration and binding energy E b between Cu and complexes.…”

“…For evaluating the gettering efficiency, we have determined the dissociation energy between Cu and electronic dopants [3]. The dissociation energy E diss is the sum of the diffusion barrier E d and the binding energy E b of a TM atom and a dopant atom, E diss = E d + E b .…”

Gettering mechanism of transition metals in silicon calculated from first principles

“…[3,4]. The first-principles pseudo potential method based on the local-density approximation (LDA) were used for the calculation.…”

“…It should be noted here that this interpretation should not be accepted literally. In fact, there is also an opposite case for this simple interpretation based on the Coulomb interactions [3].…”

“…In previous papers (Refs. [3,4]), we have developed a theoretical approach to predict the gettering efficiency among various combinations of electronic dopant atoms. In those papers, we concentrated ourselves to Cu for the target impurity, because of its practical importance.…”