NONDESTRUCTIVE MEASUREMENT OF POROUS SILICON THICKNESS USING X-RAY REFLECTIVITY

In this paper, we describe a nondestructive method based on x-ray refl ectivity for measuring the thickness of porous silicon layers as well as the interfacial roughness between the porous silicon and the single -crystal silicon substrate. Thickness and interfacial roughness measur ed using this method compare favorably with values measured using tran smission electron microscopy and atomic force microscopy but differ fr om values obtained by gravimetric techniques for porous silicon layers thinner than 150 nm.