Effect of Dimethylformamide, Current Density and Resistivity on Pore Geometry in P-type Macroporous Silicon

A systematic study was done to fabricate Macro porous silicon films by electrochemical etching of p--type silicon with a resistivity range of 0.1–5.0 Ω cm for 60 min in an electrolyte containing hydrofluoric acid (HF), water, and dymethylformamide (DMF). Samples were studied using scanning electron microscopy. The morphology of macropore formation was observed varying HF, DMF ratio in the solution, substrate resistivity and anodization current density. Cross-sectional micrographs revealed macropores of approximately columnar shape, but for low resistive substrate pore walls are fragile. A consistent variation of average poe density and average pore length was observed.