Fast Macropore Etching via Large Current and High HF Concentration on P-type Silicon

Etching rate of macropores silicon is important to the application of porous silicon for massive production. In this study, we demonstrate a fast macropore etching on p-type silicon. HF-containing electrolytes were modified with organic solvent, dimethylformamide (DMF), and 1-2 mu m macropores with nice quality were fast produced on p-type silicon substrate. The effects of HF concentration and current densities on the macropore etching rate have been investigated. By applying large current densities and HF concentration, an etching rate as high as 1900 mu m/h (approx 32 mu m/min) was achieved in our work, along with rather straight and smooth sidewalls.