A time-of-flight detector for heavy ion RBS

Abstract

We describe the details and performance of a time-of-flight (TOF) spectrometer for application in heavy ion RBS. An energy resolution of better than 1% is achieved for ^(16)O and ^(35)Cl ions in the energy range between 3 and 15 MeV. Using ions with a mass up to 45 amu as projectiles a mass resolution between 1 and 2 amu is obtained over the whole periodic table. At the sample surface a depth resolution of ∼ 1 μg/cm^2 can be achieved. The technique has been used to measure indium profiles in In GaAs/GaAs quantum well samples with a depth resolution of 2 nm, and to determine the arsenic loss in annealed GaAs samples. Further applications and improvements of the spectrometer will be discussed.

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