M. Milan et al., DEPTH PROFILING OF PHOSPHORUS IN PHOTONIC-GRADE SILICON USING LASER-INDUCED BREAKDOWN SPECTROMETRY, Applied spectroscopy, 52(3), 1998, pp. 444-448
Laser-induced breakdown spectrometry (LIBS) has been evaluated for dep
th profiling of phosphorus doping in silicon. Laser plasmas were forme
d by focusing a Nd:YAG laser (operating in the second harmonic, 532 nm
) on the sample surface. Plasma emission was collected, dispersed, and
detected with the use of a charge-coupled device (CCD). Experimental
parameters, such as delay time and sample position relative to the las
er focal point, were optimized to improve the signal-to-background rat
io of phosphorus line emission. Diffusion profiles by LIBS of samples
with different phosphorus diffusion steps are shown. Crater depth per
pulse and ablated mass per pulse were measured to be 1.2 mu m pulse(-1
) and 50 ng pulse(-1), respectively. The knowledge of depth per pulse
permitted the estimation of thickness of the P diffusion layer.