High‐performance time‐of‐flight secondary ion mass spectrometry (TOF SIMS); characterized by high mass resolution, extremely high sensitivity, and high dynamic range, has been applied to surface analysis of GaAs and Si wafers. Mass separation of metal and hydrocarbon ions of identical nominal masses allows the unambiguous detection of metal contaminants, even in the presence of heavy surface contamination by hydrocarbons. In favorable cases surface sensitivities in the ppm range are achieved. Quantitative element analysis and detection of molecular surface contaminants are possible.