NOVELTY - The method comprises cleaning a surface of a semiconductor unit of a photovoltaic device by etching such as chemical dry etching, chemical wet etching, physical etching, ion beam etching and plasma etching, drying the surface of the semiconductor unit in an oxygen-free or oxygen-depleted environment, and depositing a passivation layer on the surface by reactive sputtering using nitrogen and ammonia gas as reactive gas mixture and argon as process gas. The cleaning, drying and deposition steps are carried out in a sequence during which semiconductor unit is arranged in oxygen-free atmosphere.    USE - Method for producing a photovoltaic device or solar cells having a semiconductor unit.    ADVANTAGE - The method is capable of easily and simply producing the photovoltaic device with high efficiency and less energy consumption.    DETAILED DESCRIPTION - The method comprises cleaning a surface of a semiconductor unit of a photovoltaic device by etching such as chemical dry etching, chemical wet etching, physical etching, ion beam etching and plasma etching, drying the surface of the semiconductor unit in an oxygen-free or oxygen-depleted environment, and depositing a passivation layer on the surface by reactive sputtering using nitrogen and ammonia gas as reactive gas mixture and argon as process gas. The cleaning, drying and deposition steps are carried out in a sequence during which the semiconductor unit is arranged in oxygen-free atmosphere. The semiconductor unit comprises a first area of a first conductivity type and a second area of a second conductivity type forming a semiconductor junction between first and second areas. The cleaning step comprises an etching bath in diluted hydrofluoric acid, and rinsing in de-ionized water. The drying step comprises flushing the semiconductor unit with a dry inert gas, reducing the ambient pressure in a vacuum chamber down to a pressure of 10-7 mbar between near vacuum and a pressure below atmosphere, heating the semiconductor unit up to a temperature of 700 degrees C, exposing the semiconductor unit to microwaves, and reducing oxygen content in gas supplied to or present in an airtight chamber in which the semiconductor unit is located during drying. The composition of the reactive gas mixture is set to define hydrogen content of the deposited layer and set to 1:99-99:1 for the ratio of nitrogen:ammonia, and is varied during deposition. The deposition step is carried out continuously in an in-line coating apparatus and/or in a vacuum chamber where a pressure of 0.1-15 mu bar is set. Hydrogen containing silicon nitride is deposited as passivation layer, which is designed as an anti-reflection coating. The cleaning step, drying step and depositing step are carried out at the same surface at a side of the semiconductor unit, which is designed to be exposed to light. The semiconductor unit comprises out of doped and un-doped single-crystalline and multi-crystalline silicon. INDEPENDENT CLAIMS are included for:    (1) an apparatus for producing a photovoltaic device with a semiconductor unit; and    (2) a photovoltaic device.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic view of an apparatus for producing a photovoltaic device.    Apparatus (10)    Substrate carrier (11)    Transport path (12)    Treating chambers (13, 14, 15, 16)    Substrate. (20)