Influence of Current Density on Morphology of Electrochemically Formed Porous Silicon

Porous silicon samples were prepared by electrochemical anodic etching of p–type silicon wafer in hydrofluoric (HF) acid-based solution. The electrochemical process allowed precise control of porous silicon properties, such as average pore diameter, average pore depth and porosity. The effect of current density on physical properties of porous silicon was investigated by Scanning Electron Microscopy (SEM), I-V characteristics and Fourier Transform Infrared (FTIR) spectroscopy. The average pore diameter and average pore depth were found to increase with the increase in current density. The average pore diameter varied from (10 to 28) nm and the average pore depth varied from (470 to 2200) nm, when the current density was changed from (5 to 36) mA/cm² for 10 minutes. In addition, Al/porous/crystalline silicon sandwich showed a good rectification device.