Inline plasma etching of silicon oxides and nitrides for dry processing in silicon solar cell fabrication

Investigations on crystalline silicon solar cells using production capable etching equipment were carried out in order to examine its suitability for the substitution of wet chemical fabrication steps in solar cell production. By applying technologies for the etching of silicon oxides and/or nitrides as well as pure silicon to a single-ended industrial inline reactor different gas combinations and different types of plasma generation were assessed in terms of their ability for the implementation in an industrial production line. Etch rates of more than 30 nm/min for SiO2 and 100 nm/min for SiN as well as selectivities of SiO2 over Silicon of more than 3 achieved in a laboratory system created the base for the development of an inline production device. Process transfer was performed successfully and first processing of solar cells has been carried out. Possible applications such as PSG removal, saw damage etching and texturing as well as removal of silicon nitride after passivation have been investigated.