X-ray Reflectivity Investigation of Thin P-Type Porous Silicon Layers

X-ray reflectivity (XRR) was used to investigate the p- and p+ -type porous Silicon (PS) layers. For p- -type samples, a linear dependence of the thickness versus the anodization time was revealed in the 10-250 nm thickness range for even very short etching times and the layer structure was homogeneous with a transition layer at the PS/substrate interface. For p+ -type materials, a surface film was unexpectedly observed for layers of low porosity. The structure and origin of this surface film is discussed in this article.