Etching mixture used in production of structured surfaces on multi-crystalline, tri-crystalline and monocrystalline silicon surfaces of solar cells contains hydrofluoric acid and mineral acids selected from nitric acid

摘要

An etching mixture contains hydrofluoric acid and mineral acids selected from nitric acid, sulfuric acid and phosphoric acid. An Independent claim is also included for the production of structured surfaces on multi-crystalline, tri-crystalline and mono-crystalline silicon surfaces of solar cells or on silicon substrates used in photovoltaic cells comprising contacting the above etching mixture with the whole surface by spraying, dipping or by capillary or meniscus coating to produce isotropic etching; and washing off the etching mixture. Preferred Features: The etching mixture additionally contains an oxidant selected from hydrogen peroxide, ammonium peroxide sulfate and perchloric acid.