Identification of ultra-thin layers by cross-sectional Raman spectroscopy

Abstract

 Micro-Raman spectroscopy measurements in a cross-sectional sample geometry were performed for three heterosystems (3C-SiC/Si(100), diamond/Si(100), and ZnS_xSe_1-x/GaAs(100)). Using an automated xy-stage with a minimum step width of 100 nm one-dimensional scans across the interface were taken. It is demonstrated that sufficient sensitivity for the detection of ultra-thin layers with thicknesses in the nanometer range can be achieved. Thus surface and interface layers not accessible in a plane-view geometry can be identified. In addition, the depth-resolved variation of sample properties like interfacial reactions, stress, and stoichiometry will be discussed.