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

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 10(18)( )-10(20) 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 10(18) 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.

Automated summary

The study demonstrates that ultraviolet micro-Raman spectroscopy on small-angle beveled surfaces can produce a Raman-based doping profile with high sensitivity and resolution. The technique is able to replicate doping profiles down to 100 nm with excellent sensitivity and vertical resolution, making it suitable for heavy doped silicon in modern nanoelectronics.