SURFACE AND TOMOGRAPHIC DISTRIBUTION OF CARBON IMPURITIES IN PHOTONIC-GRADE SILICON USING LASER-INDUCED BREAKDOWN SPECTROMETRY

Laser-induced breakdown spectrometry (LIBS) has been tested as a metho d for surface analysis of photonic-grade silicon. A pulsed nitrogen la ser (337.1 nm) was used to create a microplasma on the silicon, the li ght from which was dispersed and detected by a charge-coupled device ( CCD) detector. A total area of 3 x 2.1 mm(2) was analysed with a later al resolution of 70 mu m and depth resolution of about 0.16 mu m. Fact ors affecting lateral and depth resolution of the approach were studie d. Two- and three-dimensional distribution maps of carbon contaminatio n on silicon are presented. Mapping by LIES seems to be a powerful too l to use for the 3D characterisation of solid samples combining in a s ingle step, surface and subsurface analysis capabilities.