Modeling of the effect of the buried Si–SiO2 interface on transient enhanced boron diffusion in silicon on insulator

Abstract

The effect of the buried Si–SiO2 interface on the transient enhanced diffusion (TED) of boron in silicon on insulator (SOI) structures has been investigated. To this purpose, boron marker layers were grown by chemical vapor deposition on Si and SOI substrates and implanted under nonamorphizing conditions with 40 keV Si+ ions. The experimental results clearly confirm that the Si–SiO2 interface is an efficient trap for the Si interstitial atoms diffusing out of the defect region. Based on these experiments, existing models for the simulation of B TED in silicon have been modified to include an additional buried recombination site for silicon interstitials. The simulation results provide an upper limit of ∼5 nm for the recombination length of interstitials at the Si–SiO2 interface.