Dose effects during solid phase epitaxial regrowth of boron-implanted, germanium-amorphized silicon induced by rapid thermal annealing

Abstract

The effect of implanted boron concentration on the solid phase epitaxial regrowth (SPER) kinetics during rapid thermal annealing (RTA) of 73Ge+-amorphized 〈100〉 silicon in the temperature range 500–575 °C has been studied using Rutherford backscattering and channeling measurements. Relatively flat 11B+ profiles at 5×1019, 1020, and 3×1020 cm−3 were implanted up to a depth ≂0.18 μm into different 73Ge+-preamorphized 75-cm-diam wafers. Following a RTA anneal at 800 °C/10 s (in order to recrystallize the amorphized layer and activate the implanted boron), the wafers were reamorphized with 73Ge+ ions (constant concentration ≂3×1020 cm−3 up to a depth ≂0.2 μm) and the SPER kinetics studied as indicated above. This procedure ensured that the defect densities in the wafers were the same in spite of their different boron doses. Our results clearly show an activation energy reduction from 2.86 eV at 5×1019 atoms/cm3 to 2.6 eV at 3×1020 cm−3 (in spite of the constant defect concentration in the wafers), with a linear relation between the growth rate and the implanted dose throughout the temperature range of study.