Formation and evolution of small B clusters in Si: Ion channeling study

Abstract

B off-lattice displacement in B-doped Si was observed under Si self-interstitials $(Is)$ supersaturation induced by ion irradiation at room temperature. B lattice location has a characteristic channeling mark and was studied by nuclear reaction analyses and ion channeling technique, through the comparison of the performed angular scans along the $⟨100⟩$ and $⟨110⟩$ crystal axes and the simulated scans by FLUX code. Solid and liquid-phase epitaxies and molecular beam epitaxy were used to prepare B-doped Si samples in order to investigate samples with B concentration in the range between ${10}^{19}$ and ${10}^{21}\text{ }\text{at}/{\text{cm}}^{3}$. B off-lattice displacement is limited by the fluence of excess $Is$ per B atom. Small $\text{B-}Is$ clusters (BICs) were formed as consequence of the interaction with $Is$ produced during the ion irradiation. Clusters structures were investigated by simulating the channeling angular scans of cluster configurations predicted by theoretical calculations. In the early stage of $Is$ injection, experimental observations are consistent with the presence of the predicted ${\text{B}}_{2}I$ clusters. These small BICs evolved into different structures under further ion irradiation.