Boron-doped, single (∼54 nm) or double (∼21 + 54 nm) Si1−xGex layers were epitaxially grown on 300-mm-diameter p−-Si(100) device wafers with 20 nm technology node design features, by ultrahigh vacuum chemical vapor deposition. The Si1−xGex/Si wafers were annealed in the temperature range of 950–1050 °C for 60 s to investigate the effect of annealing on possible changes of Ge content and Si stress near the Si1−xGex/Si interface. High spectral resolution, micro-Raman spectroscopy was used as a nondestructive characterization technique with five excitation wavelengths of 363.8, 441.6, 457.9, 488.0, and 514.5 nm. Ge diffusion and generation of compressive stress at the Si1−xGex/Si interface were measured on all annealed wafers. Ge diffusion and the accumulation of compressive Si stress after annealing showed significantly different behaviors between single- and double-layer Si1−xGex/Si wafers. Raman characterization results were compared with secondary ion mass spectroscopy and high-resolution x-ray diffraction results.

The possibility and suitability of micro-Raman spectroscopy as a noncontact, in-line measurement technique for boron (B) concentration in ultrathin (20~35 nm thick) Si1–xGex layers epitaxially grown on 300 mm diameter p−-Si(100) wafers, by ultrahigh vacuum chemical vapor deposition, was investigated. Raman spectra from Si1–xGex/Si(100) wafers were measured under 363.8, 457.9, 488.0, and 514.5 nm excitation. Strong correlation was found between B content and characteristics of the Si–Si Raman peak from the Si1–xGex films. As B concentration increased from undoped to 9.1 × 1020 atoms/cm3, the Si–Si Raman peak broadened and the peak height became smaller for a given Ge content. The B concentration in Si1–xGex film estimated from Raman measurement was in good agreement with secondary ion mass spectroscopy analysis results. Boron concentration as low as 8.7 × 1017 atoms/cm3 can be detected by Raman spectroscopy, which is ~30 times more sensitive than the detection limit (2.7 × 1019 atoms/cm3) of high-resolution x-ray diffraction.