ERDA

A technique for depth profiling of light elements and isotopes

For the analysis heavy ions of typically several 10 MeV energy are used. The elastically scattered ions and recoiled target atoms are detected in foreward direction by particle identifying detection techniques:

• A Bragg Ionisation Chamber separates light particles according to atomic number
• A Time-Of-Flight telescope separates light and medium particles according to mass number (isotopes)
• A Si-detector telescope separates H- and He-isotopes

Example parameters

• Ions: 35 MeV Cl⁷⁺, 2 - 10 nA
• Analysing depth: Several 100 nm
• Detection limit: 0.1 at% in volume, 5×10¹⁴ at/cm² as thin film
• Depth resolution: 10 nm (except for H and He)