Low energy ion scattering as a depth profiling tool for thin layers - Case of bromine methanol etched CdTe

We have investigated the properties of the Te-rich surface layer formed after a bromine-methanol etch of CdTe single crystal by two methods: Angle Resolved X-Ray Photoelectron Spectroscopy (ARXPS) and Low Energy Ion Scattering (LEIS) in the Dynamic mode. We compare the acquisition time of each method. The results showed similar, exponential decay of the Te/Cd ratio to a depth of 6 nm. At the depths higher than 6 nm, the substrate becomes stoichiometric. Dynamic LEIS provided more detailed information about composition at depths lower than the probing depth of ARXPS. The Dynamic LEIS measurements suggest that the composition of the outermost layer of CdTe after bromine-methanol etching consists of CdTe4.