Ni-activated photo-electrochemical formation of por-Si in HF/H2O2/H2O Solution

The kinetic of Ni-assisted chemical etching in the solution HF/H
₂
O
₂
/H
₂
O, morphology and composition of porous Si are investigated. Mechanism of etching corresponds to well known metal-assisted chemical etching process. It is shown that porous silicon formation on p-Si covered with Ni thin film consists of two simultaneous steps: metal-assisted and photo-electrochemical etching. It was shown that the result of Ni-assisted chemical etching of p-Si is black silicon that exhibits high absorptance property. Enhanced light absorption occurs on black silicon results in photo-electrochemical formation of porous silicon. Illumination - assisted holes play main role in photo-electrochemical etching. Etching mechanism has been considered in terms of contact corrosion and band theory.