Non-Contact and Non-Destructive Characterization of Laser Spike Annealed Si1-xGex/Si Using Very High Resolution Multiwavelength Raman Spectroscopy

Abstract

Undoped and B doped Si1-xGex epitaxial layers, on Si(100) wafers with various Ge content and Si1-xGex layer thickness, were prepared and annealed by a laser spike annealing (LSA) system using a 10.6 μm laser beam to investigate the effect of LSA on the integrity of Si1-xGex/Si. Various target wafer temperatures and dwell times were used in the LSA steps. Ge content and lattice level stress were characterized using a multi-wavelength, high resolution micro-Raman (MRS-300) system before and after LSA exposures with various temperatures and dwell times. Strain relaxation of the Si1-xGex and Si was observed, post-LSA, for exposures exceeding a critical temperature (>1190oC). The critical temperature for strain relaxation was higher for Si1-xGex epitaxial layers with low Ge content or high B dopant concentration in the Si1-xGex epitaxial layers.