In-situ non-disruptive cleaning of Ge(100) using H2O2(g) and atomic hydrogen

In-situ gas phase cleaning of the Ge(100) surface was studied at the atomic level using scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) while chemical analysis of the surface was performed using X-ray photoelectron spectroscopy (XPS). High purity H2O2(g) dosing removed carbon contamination from an air exposed Ge(100) sample. The oxide formed via H2O2(g) dosing was subsequently removed via either atomic hydrogen exposure at 300 degrees C or 550-700 degrees C annealing. STM imaging showed an air exposed Ge(100) surface after H2O2(g) dosing and 600-700 degrees C annealing produced a flat and ordered surface while STS verified the density of states (DOS) is equal to that of a Ge(100) surface which has been cleaned via sputter (500 degrees C) and annealing (700 degrees C). Combining H2O2(g) with atomic hydrogen dosing or annealing removed carbon via oxidation and oxygen via thermal desorption or reduction from an air exposed Ge(100) surface. (C) 2014 Elsevier B.V. All rights reserved.