Micro-Raman investigation of p-type B doped Si(100) revisited

Abstract The doping concentration of B doped single-crystal Czochralski Si(100) wafers (6x1014-5x1019 cm-3) has been monitored via micro-Raman spectroscopy using visible (633 and 532 nm) and near-UV (355 nm) laser excitations at low power (5 mW). Data have been analysed with unprecedented accuracy via a convoluted Fano-Gaussian model of the first-order Raman Stokes mode of Silicon. This allowed the determination of the fitting spectral parameters (peak position and width) with an accuracy of 0.01 cm-1, that enables a reliable probing of the concentration. We observed, independently on the excitation wavelength used, a widening (up to 6.5 cm-1), a frequency-softening (up to 1.5 cm-1) and an intensity reduction (down to 90 % ) of the Si peak with the doping concentration. The widening and frequency-softening follow a strictly linear dependence with doping concentration, allowing a calibration. A linear dependence of the reciprocal Fano asymmetry parameter ( q - 1 ) with excitation energy is verified, with the slope showing a linear behavior with the doping concentration and providing a direct estimate on the hole-phonon interaction strength. Results are reproduced with surface-sensitive near-UV Raman spectroscopy on BF 2 + ion implanted and laser thermal annealed (LTA) Si, demonstrating the full portability of the Raman technique to state-of-the-art nanoelectronics.