Silicon solar cells technology using honeycomb textured front surface

This paper presents a new silicon solar cell structure obtained by the front surface texturisation using silicon micromachining technologies. A ´honeycomb´ textured front surface has been obtained using a photolitographic process to generate patterns (disc holes) on the top surface followed by isotropic etching in HNO₃ : HF : CH3COOH up to join together of the wells. For the front surface losses characterization, the spectral dependence reflection has been investigated by spectrophotometric measurements. The surface reflectivity was lowered at 5% (30% in the case of untextured monocrystalline surface). The p-n junction made by phosphorus diffusion at ∼0.8 μm follows the honeycomb profile. In order to ensure low series resistances a p+ bor diffusion on the back of the structure was made. The fabrication process was completed with an ohmic contacts (Al: on top and on the back surface).