SIMS Linescan Profiling of Chemically Bevelled Semiconductors: A Method of Overcoming Ion Beam Induced Segregation in Depth Profiling

Abstract

Copper implanted p-type silicon samples were investigated using secondary ion mass spectrometry (SIMS) depth profiling with positive oxygen primaries incident at a variety of angles. Beam induced segregation leads to considerable distortion of the profile if the beam was incident at angles between normal and 30°. These results were consistent with SIMS work on thin films of copper on p-type silicon. The copper implanted material was chemically bevelled. SIMS linescan profiles of the chemically bevelled samples yielded accurate copper profiles free of beam induced segregation. The pile-up of the Cu at the SiO₂/Si interface during oxygen depth profiling at normal incidence was observed by chemically bevelling a SIMS crater that had been synthesised with an oxygen primary beam. The location of the copper atoms with respect to the altered layer (i.e. the internal profile) was then found by linescanning down the bevel plane.

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