Doping profiling of beveled Si wafers via UV-micro Raman spectroscopy

Highlights: • Doping profiling of p-type Si via UV micro-Raman spectroscopy on beveled surfaces. • The Raman-based method does not require independent doping characterization. • The technique has high lateral (1 $\mu$m) and vertical (10 nm) resolution and doping sensitivity (10${}^{18}$ cm${}^{-3}$). • Raman doping profiling is proved as an alternative to standard techniques like SIMS and SRP. • Raman doping profiling is suitable for shallow Si-based nanoelectronics. Doping profiling methods are required to provide doping monitoring of heavy doped Silicon wafers, widely used in electronic devices, with high concentration sensitivity and spatial resolution. Herein, we demonstrate that ultraviolet (UV) micro-Raman spectroscopy implemented on small-angle beveled surfaces is able to produce a Raman-based doping profile without any further measurements. The reliability of the approach is verified on ion-implanted p-type B-doped single-crystalline Si (100) wafers with shallow (100 nm) doping profile, directly comparing the Raman-based doping profiling results with independent secondary ion mass spectrometry (SIMS) and spreading resistance profiling (SRP) measurements. The Raman-based technique is capable to fully reproduce the doping profile down to 100 nm with excellent doping sensitivity (10 ppm) in the 10¹⁸–10²⁰ cm⁻³ doping concentration range providing high lateral (vertical) resolution of $1\mu m$ (10 nm). The technique is comparable to SIMS in terms of resolution and sensitivity down to 10¹⁸ cm⁻³ concentration but requires the beveling process. Instead, it is a better alternative to SRP on bevel due to its higher spatial resolution and avoiding probe contact. The Raman-based doping profiling technique is, therefore, suitable for heavy doped Si with typical shallow doping profiles of state-of-the-art Si-based nanoelectronics.