Influence of the doping type and level on the morphology of porous Si formed by galvanic etching

The formation of porous silicon ($por$-Si) layers by the galvanic etching of single-crystal Si samples (doped with boron or phosphorus) in an HF/C$_{2}$H$_{5}$OH/H$_{2}$O$_{2}$ solution is investigated. The $por$-Si layers are analyzed by the capillary condensation of nitrogen and scanning electron microscopy (SEM). The dependences of the morphological characteristics of $por$-Si (pore diameter, specific surface area, pore volume, and thickness of the pore walls), which determine the $por$-Si combustion kinetics, on the dopant type and initial wafer resistivity are established.