Linear radio frequency plasma sources for large scale industrial applications in photovoltaics

Abstract

Linear plasma sources can be used both in PECVD-processes for deposition of dielectric layers like oxides or nitrides and for plasma etching of substrates at dimensions of more than 1×1 m2. Furthermore effective plasma surface modification or simple surface plasma cleaning can be carried out. A high substrate throughput is achieved by using inline vacuum processes with typical process times of 60 s for 1 m2 substrate area.Besides well developed linear microwave plasma sources applied to industrial large scale silicon nitride deposition for photovoltaics, linear radio frequency plasma sources become more and more important to generate linear plasmas for applications like deposition of amorphous and microcrystalline silicon or reactive ion etching.The principle of linear radio frequency plasma sources is shown. An additional magnetic field enhances both the process pressure range (down to 10−3 mbar) and the plasma density.Results of silicon nitride deposition and of hydrogen passivation at multicrystalline silicon wafers are presented.