The deposition of perfect growing layers requires an atomically clean surface. In this paper we will describe a new in situ cleaning technique which is able to reduce the temperature/time load of silicon substrates significantly.
First we will investigate the efficiency of the in situ UV/ozone cleaning immediately before deposition. Such an UV/ozone treatment lowers the level of impurities below the detection limit of in situ XPS. The known recontamination if exposing to air after ex situ cleaning is prevented by this in situ technique.
Nevertheless a significant contamination within the UHV chamber is detected by SIMS. A comparison of various UHV pumping systems (base pressure in the range of 10-8 Pa) shows the specific influence on recontamination at an atomically clean surface.
A blocking mechanism by a thin oxide layer below (0.1 ML) to avoid the growth of stacking faults within an epitaxial silicon layer was successfully tested.