Analysis of buried etch-stop layers in silicon by nitrogen-ion implantation

The analysis of the etch-stop properties of layers obtained by substoichiometric nitrogen-ion implantation and annealing in silicon has been performed as a function of the implantation conditions. The analysis of the etching efficiency has been tested in TMAH-IPA systems. The results obtained show the need to implant at doses higher than 2 x 1017 cm-2 to obtain etch-stop layers stable under high-temperature annealing. So, for implantation doses of 5 x 1017 cm-2, layers stand unetched for times longer than 2 h. The preliminary structural analysis of the samples suggests the presence of an amorphous silicon nitride layer for higher implantation doses. (author)