The role of hydrogen in the formation of porous structures in silicon

The role of hydrogen in the formation of porous silicon (PS) structures is assumed to passivate dangling bonds of the surface silicon atoms. The formation of surface hydride complexes SiHx (x=1,2,3) is well documented using infrared absorption spectroscopy and other methods of chemical analysis. In the present work we show by means of infrared spectroscopy of PS films subjected to different post-anodising chemical treatments that hydrogen atoms are incorporated into the corroding silicon wafer through easy paths which are generated in the vicinity of the pore tips as a result of the combined action of the electrolyte solution and dynamic mechanical stress generated during the dissolution reaction.