High productive deposited Mo layers for back ohmic contacts of solar cells

In the paper, thin molybdenum (Mo) layers produced by magnetron sputtering [state of the art in production for photovoltaic applications (PV)] are compared with those produced by high-rate electron beam (EB) deposition technology. Stainless steel and borofloat glass served as substrate materials. Mo layers deposited by DC-magnetron sputtering were produced as a reference and investigated by analysis of structure and specific electrical resistance. Alternative layers prepared by high-rate EB-deposition with a rate up to 240 nm·s-1 were characterised by inquests of mechanical properties, sheet resistance and cell efficiency. A strong dependency of specific electrical resistance on residual gas conditions was determined. The specific electrical resistance dropped from 18 to 11 µ·cm. Compactness of Mo layers increased with implementation of plasma activation. The layer formation became denser and comparable to the magnetron sputtered Mo layers.