Substitutional platinum as an efficient nonradiative recombination center in silicon

TL;DR

This study uses first-principles calculations to reveal how substitutional platinum acts as an efficient nonradiative recombination center in silicon, with implications for carrier lifetime control.

Contribution

It provides a microscopic understanding of the carrier capture mechanisms of substitutional platinum in silicon, highlighting the role of defect configurations and Jahn-Teller distortions.

Findings

Substitutional platinum exhibits large carrier capture cross sections for electrons and holes.

The capture cross sections are sensitive to Jahn-Teller distortions and defect configurations.

Calculated cross sections match experimental data when considering multiple defect configurations.

Abstract

Platinum (Pt) is widely used for carrier-lifetime control in silicon power devices, yet the microscopic nonradiative recombination mechanism of the substitutional platinum ($\text{Pt}_\text{Si}$) dopant remains debated. Using first-principles calculations combined with nonradiative multiphonon theory, we systematically investigate the electronic structures and carrier capture dynamics of $\text{Pt}_\text{Si}$. Our results show that both the donor ($+/0$) and acceptor ($0/-$) levels of $\text{Pt}_\text{Si}$ exhibit large capture cross sections for electron and hole carriers, thereby making $\text{Pt}_\text{Si}$ an effective recombination center. Notably, the calculated capture cross sections are sensitive to the symmetry-equivalent defect configurations with different Jahn-Teller distortions. By accounting for two different $D_{2d}$ configurations of neutral $\text{Pt}_\text{Si}$ during transitions properly, our calculated carrier capture cross sections align well with experimental values. This work provides a microscopic picture of the carrier capture processes induced by $\text{Pt}_\text{Si}$ and emphasizes the importance of symmetry-equivalent configurations in defect-assisted nonradiative recombination.