In-line Si1-xGex epitaxial process monitoring and diagnostics using multiwavelength high resolution micro-Raman spectroscopy

摘要

Multiwavelength, high resolution micro-Raman spectroscopy was applied to in-line process monitoring and diagnostics of undoped and B-doped Si1-xGexepitaxy on Si(100) device wafers. This noncontact technique was used to monitor the Ge content, B concentration and thickness of single and double Si1-xGexepitaxial layers. Epitaxial process problems were diagnosed nondestructively. Raman peak positions and full-width-at-half-maximum of the Si-Si peak(s) from the Si1-xGexepitaxial layer(s) and Si substrates, in the wavenumber range of 475 ～ 535 cm-1, were monitored under ultraviolet and visible excitation wavelengths. The Ge content, B concentration and Si1-xGexepitaxial film structures were verified by secondary ion mass spectroscopy(SIMS) depth profiling results. In-line monitoring of Si-Si and Si Raman peaks is very effective in noncontact material property characterization, epitaxial process optimization, and quality control applications.