Impact of Laser Anneal Thermal Budget on the Quality of Thin SiGe Channels with a High Ge Content

We explore the limits of sub-melt laser annealing on blanket SiGe/Si-cap layers with Ge concentrations up to 55% using High-Resolution X-ray Diffraction (HR-XRD) and a new non-contact metrology to measure the mobility of inversion charges. We discuss the influence of the laser peak temperature and SiGe/Si stack parameters. It is shown that for high Ge concentrations and SiGe/Si-cap thicknesses of interest, the standard laser anneal thermal budget needs to be limited to avoid excessive relaxation and to preserve the mobility enhancement.