Porous Silicon

A porous silicon layer results from an electrochemical etching of a crystalline silicon wafer in a hydrofluoric acid based electrolyte. Various morphologies can be obtained depending on the type, the doping level, the crystalline orientation of the Si wafer and also on the electrolyte composition. Pores are open and “grow” mainly in the current direction. Their sizes vary from a few nanometers (mesoporous) to several micrometers (macroporous). The porous layer thickness mainly depends on the applied current density and duration. SiLiMiXT is specialized in the fabrication of porous silicon at wafer scale. In collaboration with SIL’TRONIX, SiLiMiXT can produce for you single porous layers on their quality silicon material.

More complex structures can be built by applying modulated currents or by changing the electrolyte composition in order to create porosity gradients or layered structures such as Bragg mirrors. Anodic conditions are generally specific to each structure.

SiLiMiXT can takes up the development. For all development, please contact SiLiMiXT.

        Si poreux.jpg              Mix 1 Mix 2 Mix 3 Mix 4
Diameter 4" 4" 6" 6"
Type - Dopant  P - Boron   P - Boron   P - Boron   P - Boron 
Orientation (100) (100) (100) (100)
Resistivity (Ohm.cm)  0.01-0.02   0.01-0.02   0.01-0.02   0.01-0.02 
Back side surface etched etched polished polished
Wafer thickness (µm) 500-550 500-550 650-700 650-700
Porous thickness (µm) +/-10% 10 30 10 30
% porosity (+/-10%) 40 40 40 40


For other specifications, please contact Silimixt: www.silimixt.com