Use of Sirtl etch for silicon-slice evaluation.

An investigation was conducted to explore the possibility of using Sirtl etch as a nondestructive evaluation step for categorizing silicon wafers before device fabrication is begun. It is known that chromium is deposited as a residue during the chemical reaction associated with etching silicon in Sirtl etch. There has been concern that the use of Sirtl etch could result in the diffusion of chromium into the silicon slice during subsequent high-temperature processing steps. The investigation revealed, however, that residual chromium resides only on the surface of the slice and can easily be removed.