Formation of porous layers on InSb(100) by anodization

Abstract

The present work deals with anodization processes of n-type InSb(100). Preferential etching of InSb can be electrochemically initiated in HCl, HBr and HF solutions. Except for etch features also the formation of porous layers can be observed. The resulting features were characterized by SEM and AES measurements. Due to the narrow bandgap of the material the results of the anodization process are neither sensitive to illumination of the n-type material nor to the doping level. The morphology of the attack depends strongly on the electrochemical conditions and the type of halogen acid present in the electrolyte. In HCl and HBr a black porous layer can be formed that is likely to consist to a certain extent of an antimonyoxo-chloride or antimony-oxo-bromide.In HF, however, polarization under a wide range of electrochemical conditions leads to a uniform etching of the InSb surface.

Electrochemical pore formation onto semiconductor surfaces

“…6, the counter anions X À in halogen acids (with X ¼ F, Br, Cl) play a crucial role determining the pore topography [38]. Note that a porous film exhibiting a different chemical composition than the substrate is formed onto InSb in HX [151] and onto InP in (NH 4 ) 2 S [152].…”

Formation of porous layers on n-GaSb by electrochemical etching

“…In both cases, it can be noted that a steep current increase takes place at a given voltage value (around 0.06 V for HF electrolyte, and 0.24 V for HCl electrolyte). In previous works on anodization of III-V semiconductors [6,15,16] similar I-V curves have been reported, and the voltage value corresponding to the fast current increase has been defined as the pore formation potential (PFP), i.e. the potential at which electrochemical dissolution of the material begins.…”

Corrosion behaviour of heterogeneous antimony-copper layers in chloride media

“…Unfortunately, these publications neither describe the morphology of the resulting layers, nor do they present SEM images. A porous structure of Sb-alloys obtained by anodic polarisation in the presence of halide acid solutions has been reported relatively rarely [58]. Schmucki et al have shown that upon anodising n-type InSb(100) in HCl solution, black porous layers of Sb 4 O 5 Cl 2 compound are obtained.…”