A new secondary ion mass spectrometry technique for III-V semiconductor compounds using the molecular ions CsM+

We describe a new secondary ion mass spectrometry technique for compositional analysis of matrix elements. It consists of detecting the molecular ions CsM+ rather than M± ions (M is the matrix element to be analyzed) under Cs+ primary ion bombardment. The linear behavior of the CsM+ ion yield makes the analysis independent of the matrix effect. An application to in-depth quantitative compositional analysis for AlGaAs/GaAs multilayer structures is given. The compositions were determined with an absolute accuracy better than 2% and the depth resolution was smaller than 100 Å.