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Abstract
Phosphorus (P) is one of the most widely used donor dopants for fabricating a lowresistivity silicon (Si) substrate. However, its volatile nature and the relatively small equilibrium segregation coefficient in Si at the melting temperature of Si impede the efficient and effective growth of lowresistivity Czochralski (CZ) Si single crystal. The primary objective of this work is to theoretically perceive the influence of germanium codoping on the heavily Pdoped Si crystal by means of CALculation of PHase Diagrams (CALPHAD) approaches and density functional theory (DFT) calculations. Phase equilibria at the Sirich corner of the SiGeP system has been thermodynamically extrapolated based on robust thermodynamic descriptions of involved binary systems, where SiP and GeP have been reassessed in this work. Phase diagram calculation results indicate that at a given P concentration (e.g. 0.33 at.% P) Ge codoping lowers the solidification temperature of the Si(Ge, P) alloys, as well as the relevant equilibrium segregation coefficients of P in the doped Si. DFT calculations simulated the formation of (i) monovacancy in Si as well as (ii) solutions of Si(P) and Si(Ge) with one dopant substitutionally inserted in 64 and 216atom Si cubic supercells. Binding energies were calculated and compared for GeGe, GeP and PP bonds positioning at the first nearestneighbors (1NN) to the third nearestneighbors (3NN). PP bonds have the largest bonding energy from 1NN to 3NN configurations. The climbing image nudged elastic band method (CLNEB) was utilized to calculate the energy barriers of P 1NN jump in the 64atom Si cubic supercell with/without a neighboring Ge atom. With Ge present, a higher energy barrier for P 1NN jump was obtained than that without involving Ge. This indicates that Ge can impede the P diffusion in Si matrix.
Original language  English 

Pages (fromto)  4272–4288 
Number of pages  17 
Journal  Journal of Electronic Materials 
Volume  50 
Issue number  8 
Early online date  21 Apr 2021 
DOIs  
Publication status  Published  Aug 2021 
MoE publication type  A1 Journal articlerefereed 
Keywords
 CALPHAD
 density functional theory
 equilibrium segregation coefficient
 formation energy
 Germanium codoping
 heavily Pdoped Si
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 1 Finished

POSITIONII: A pilot line for the next generation of smart catheters and implants
PaulastoKröckel, M., Österlund, E., Bespalova, K., Dong, H., Vuorinen, V. & Kaaos, J.
01/06/2018 → 31/05/2021
Project: Business Finland: Other research funding