Epitaxial regrowth of Ar-implanted amorphous silicon

Abstract

The influence of Ar on the recrystallization of implanted amorphous silicon layers has been studied. Investigation of the growth kinetics at temperatures up to 575 °C showed that epitaxial regrowth of silicon is halted if the Ar concentration at the amorphous–single-crystal interface reaches about 1.5×1020 cm−3. Further regrowth could be obtained by higher-temperature annealings, during which the Ar concentration profile was changed and part of the Ar diffused out. TEM analysis showed, that in samples with a dose of 6×1015 Ar ions/cm2, the formation of Ar bubbles occurred during implantation. During annealing the Ar bubbles grew about a factor of 6 in diameter. The epitaxially regrown silicon layers contained a large amount of microtwins. We present a model which relates the occurrence of microtwins to the existence of Ar bubbles.