Atomic-Scale Modification of Oxidation Phenomena on the Ge(100) Surface by Si Alloying

Properties of Geoxides are significantly different from thoseof widely used Si oxides. For example, the instability of GeO x at device junctions causes electronic defectlevels that degrade the performance of Ge-containing devices (e.g.,transistors and infrared detectors). Therefore, the passivating Silayers have been commonly used at Ge interfaces to reduce the effectsof Ge oxide instability and mimic the successful strategy of Si oxidation.To contribute to the atomic-scale knowledge and control of oxidationof such Si-alloyed Ge interfaces (O/Si/Ge), we present a synchrotronradiation core-level study of O/Si/Ge, which is combined with scanningprobe microscopy measurements. The oxidation processes and electronicproperties of O/Si/Ge(100) are examined as functions of Si amountand oxidation doses. In particular, the incorporation of Si into Geis shown to cause the strengthening of Ge-O bonds and the increaseof incorporated oxygen amount in oxide/Ge junctions, supporting thatthe method is useful to decrease the defect-level densities.