Embedded tin nanocrystals in silicon - an electrical characterization.

Tin nanocrystals embedded in a SiSn layer grown by molecular beam epitaxy on w-type Si are investigated by means of deep level transient specttoscopy. Two Sn related deep ttaps are observed, depending on the annealing temperature of the samples. A deep level at E-C - 0.62 eV (Sn1) is observed for annealing temperatures up to 650 degrees C, whereas a level at E-C - 0.53 eV (Sn2) appears for annealing temperatures above 600 degrees C. Scanning transmission electton microscopy shows the formation of Sn nanocrystals at 600 degrees C, which coincides with the appearance of Sn2. Sn1 is tentatively assigned to a Sn related precursor defect, which transforms upon annealing into either Sn nanocrystals or an interface defect located at the nanocrystal surface.