Experimental research on damage and formation limits on porous silicon materials by electrochemical etching method

Efficient silicon electrochemical etching (anodization) is essential to produce porous silicon (PSi) for a wide variety of applications, but the damage that occurs to the porous layer of the silicon during the anodization is wasteful and inefficient. The porous formation mechanism of highly doped p-type silicon was studied by considering the applicable range of the anodizing parameters and their effects on the pore formation and distribution. The results show that most of the PSi damage attributed to the severe potential drop in the developed oxide film, which promoted the reaction toward the passivation region of theI–Vcurve. There is indirect dissolution, which produces a delocalized distribution of the electrochemical reaction over the etched area; meanwhile, the internal residual stress inside the porous layer causes the pore damage. It provides a guide map for PSi formation and damage control in order to promote more effective production of PSi-based devices.Graphical abstractPorous silicon formation in p-type silicon was investigated comprehensively. Particular emphasis is put on the limitations and sensitivity of etching parameters. A neat and substantiated classification of the porous layer’s damage is set out. The formation damage is always ahead of the volumetric damage. Most of the damage is due to the high potential drop in the oxide film.