What was the atmosphere during the growth process? Vacuum? Which grade?

The fact is that I grow dichalcogenides of group IV metals and such balls often appear there. These are oxides. Or sulfo-oxides.

As I understand it, this is a photograph from an electron scanning microscope or optical microscope. If this is an SEM, then try doing an EDC or EDAX analysis.

Alexander N Titov

At first the atmosphere is only Ar gas in atmospheric pressure,during the growth time Ar+10% H2 was introduced. The image is taken from optical microscope. I also performed the raman spectroscopy on the black spots and it only shows the Si peak.