TY - JOUR
T1 - Supersaturating silicon with transition metals by ion implantation and pulsed laser melting
AU - Recht, Daniel
AU - Smith, Matthew J.
AU - Charnvanichborikarn, Supakit
AU - Sullivan, Joseph T.
AU - Winkler, Mark T.
AU - Mathews, Jay
AU - Warrender, Jeffrey M.
AU - Buonassisi, Tonio
AU - Williams, James S.
AU - Gradečak, Silvija
AU - Aziz, Michael J.
PY - 2013/9/28
Y1 - 2013/9/28
N2 - We investigate the possibility of creating an intermediate band semiconductor by supersaturating Si with a range of transition metals (Au, Co, Cr, Cu, Fe, Pd, Pt, W, and Zn) using ion implantation followed by pulsed laser melting (PLM). Structural characterization shows evidence of either surface segregation or cellular breakdown in all transition metals investigated, preventing the formation of high supersaturations. However, concentration-depth profiling reveals that regions of Si supersaturated with Au and Zn are formed below the regions of cellular breakdown. Fits to the concentration-depth profile are used to estimate the diffusive speeds, vD, of Au and Zn, and put lower bounds on vD of the other metals ranging from 102 to 104 m/s. Knowledge of vD is used to tailor the irradiation conditions and synthesize single-crystal Si supersaturated with 1019 Au/cm3 without cellular breakdown. Values of v D are compared to those for other elements in Si. Two independent thermophysical properties, the solute diffusivity at the melting temperature, Ds(Tm), and the equilibrium partition coefficient, k e, are shown to simultaneously affect vD. We demonstrate a correlation between vD and the ratio Ds(T m)/ke0.67, which is exhibited for Group III, IV, and V solutes but not for the transition metals investigated. Nevertheless, comparison with experimental results suggests that Ds(T m)/ke0.67 might serve as a metric for evaluating the potential to supersaturate Si with transition metals by PLM.
AB - We investigate the possibility of creating an intermediate band semiconductor by supersaturating Si with a range of transition metals (Au, Co, Cr, Cu, Fe, Pd, Pt, W, and Zn) using ion implantation followed by pulsed laser melting (PLM). Structural characterization shows evidence of either surface segregation or cellular breakdown in all transition metals investigated, preventing the formation of high supersaturations. However, concentration-depth profiling reveals that regions of Si supersaturated with Au and Zn are formed below the regions of cellular breakdown. Fits to the concentration-depth profile are used to estimate the diffusive speeds, vD, of Au and Zn, and put lower bounds on vD of the other metals ranging from 102 to 104 m/s. Knowledge of vD is used to tailor the irradiation conditions and synthesize single-crystal Si supersaturated with 1019 Au/cm3 without cellular breakdown. Values of v D are compared to those for other elements in Si. Two independent thermophysical properties, the solute diffusivity at the melting temperature, Ds(Tm), and the equilibrium partition coefficient, k e, are shown to simultaneously affect vD. We demonstrate a correlation between vD and the ratio Ds(T m)/ke0.67, which is exhibited for Group III, IV, and V solutes but not for the transition metals investigated. Nevertheless, comparison with experimental results suggests that Ds(T m)/ke0.67 might serve as a metric for evaluating the potential to supersaturate Si with transition metals by PLM.
UR - http://www.scopus.com/inward/record.url?scp=84885406201&partnerID=8YFLogxK
U2 - 10.1063/1.4821240
DO - 10.1063/1.4821240
M3 - Article
SN - 0021-8979
VL - 114
JO - Journal of Applied Physics
JF - Journal of Applied Physics
IS - 12
M1 - 124903
ER -