Carbon segregation at Σ3 {1 1 2} grain boundaries in silicon

Abstract

First-principles calculations were carried out to systematically investigate the carbon segregation along Σ3 {112} grain boundaries (GBs) in silicon. The energetically favorable segregation sites and corresponding segregation energy at two types of Σ3 {112} GBs, i.e. symmetric and asymmetric Σ3 {112}, were determined. A site-selective carbon segregation behavior along these two GBs was revealed, and a maximum segregation energy of -0.418 eV/atom and -0.525 eV/atom was predicted for the symmetric and asymmetric Σ3 {112} GBs, respectively. It is found that the segregation energy is linearly correlated with the average bond length (ABL) of carbon atoms segregating at the core sites in these two GBs instead of the ABL of core Si sites in the pristine Σ3 {112} GBs. Such a correlation is primarily attributed to the bonding energy effect caused by the substitution of carbon atom at the Σ3 {112} GBs, as well as the structural reconstructions of GBs along the [11 _ 0] direction. This work provides, at the atomic level, a fundamental theoretical understanding on the carbon segregation behavior at Σ3 {112} GBs in Si.

Revealing the factors influencing grain boundary segregation of P, As in Si: Insights from first-principles

“…The strong gettering ability of Σ3 {112} GBs was also recognized for other elements including C [63] and Fe [68]. The distinct segregation behavior of impurity atoms can be related to the high structural irregularity of Σ3 {112} GBs.…”

“…The properties of the GBs as investigated in the present work are summarized in Table 1, in which some previous theoretical data [35,63] are also included for comparison. Apparently, Σ3 {111} GB has the lowest GB among all the GBs.…”

Strain building and correlation with grain nucleation during silicon growth

“…The most stable situation is obtained when the Σ3 twin boundaries formed by competition can follow a common plane {111} or {112}, corresponding to a symmetric coherent and most densely packed and to a symmetric/asymmetric incoherent and second most densely packed Σ3 twin boundary, respectively [41,42]. In the case of Σ9 twin boundaries, three cases have been reported by Ervik et al [41]: two twin boundaries with {122} or {114} common planes, the first situation, corresponding to the best crystalline case and to the most densely packed CSL, and an asymmetric Σ9 twin boundary with {111}/{115} planes with a low density of coincidence sites.…”

Phase diagram of grain boundary facet and line junctions in silicon

“…In this respect, it is important to note that the ε xx strain extends deep into the bulk at the S-{112} facets. Thus different induced segregation profiles at S-and A-{112} GBs are expected [10,28]. Hence, the segregation profile will be a function of inclination angle and facet period and will be thus qualitatively described by the phase diagram if Fig.…”