Infrared analysis of epitaxial silicon layers
First a reflectance analysis of an undoped epitaxial silicon layer grown on a p-doped substrate is shown. As shown in the sketch to the right in between the undoped epi-layer and the doped substrate a carrier concentration gradient has been inserted. Gradients in optical properties can easily be defined in the SCOUT software.
From the parameter adjustment a thickness of 1.25 micrometer for the epi-layer and 0.29 micrometer for the gradient layer has been found. In addition to the layer thicknesses, the plasma frequency and the damping constant of the substrate charge carriers have been determined (810 1/cm and 241 1/cm, respectively).