USE OF REACTIVE ION SPUTTERING TO PRODUCE CLEAN GERMANIUM SURFACES INA CARBON-RICH ENVIRONMENT - AN ION-SCATTERING STUDY

We have used the ion spectroscopic techniques of direct recoil spectro scopy and mass spectroscopy of recoiled ions to demonstrate that low e nergy reactive ion sputtering of Ge is capable of removing surface imp urities such as carbon. The experiments were performed in a vacuum cha mber maintained at 3.5X10(-7) Torr. At these pressures, physical sputt ering using noble gas is not effective for cleaning Ge surfaces as car bon redeposits onto the surface. In this article, we demonstrate that reactive sputtering of Ge using 4.0 keV nitrogen at a Ge surface tempe rature of similar to 740 K and above removes surface carbon and deposi ts nitrogen on the Ge surface. Heating the nitrogen exposed Ge surface to above similar to 880 K results in the desorption of nitrogen and g enerates an atomically clean Ge surface, under poor vacuum conditions. (C) 1998 American Vacuum Society.