Role of hydrogen on pore silicon formation

Abstract EN

-The rule oj hydrogen on pore .silicon formation was performed using combined in-situ and ex-situ characterisation.

The purpose of this work is the study of the early stages of the porous structure formation in silicon during its anodic and cathodic polarization in HF solution by hydrocarbon groups(CHX) modification of the silicon-electrolyte interface .

In HF environment, this coating is stable but can be destroyed upon flowing of an anodic current.

In-situ electrochemical characterisations and FTIR absorption spectra were used on p-Si and p-Si /( CHX) during the first stages of anodization, together with ex-situ SEM observation.

After a short anodization time, the topography of the surface exhibits flat areas with sharp boundaries.

After similar electrochemical treatments, unmodified Si surfaces appear comparatively much smoother.

A SEM observation of the p-Si (III) surfaces after cathodic polarisation shows a appearance of a regular triangular dislocations, characteristics of substrat orientation .

These results confirm that hydrogen is responsible for the generation of structural defects and can he taken as an indication that H is responsible of porous initiation .