Quantification of impurity concentration in Cu2O and CuO via secondary ion mass spectrometry

Secondary ion mass spectrometry (SIMS) is a technically matured analysis technique for the investigation of depth and lateral distributions in solids. The “raw data” of a SIMS measurement provides only qualitative information. For quantification so-called relative sensitivity factors (RSF) are mandatory. To our knowledge no RSFs have been determined for Cu2O and CuO so far. In this work the RSFs for 21 elements in Cu2O and 14 elements in CuO have been determined via ion implanted standards. For the RSF determination we present the plateau method (Section 3) for box-like implantation profiles. This method provides a lower uncertainty in RSF value compared to the obtained uncertainty using single implantation profiles. In addition, we have estimated the electron affinities of NO2, AsO2 and SbO to 0.55, 2.7 and 2.85 eV, respectively. Unexpectedly, we observe for Cu2O and CuO nearly identical RSF values. This behaviour cannot be attributed to a change in chemical composition caused by the SIMS sputter process. Furthermore, the calculated RSFs have been used to determine the impurity concentrations of our sputtered copper oxide thin films.