PERC-tandem solar cell with sacrificial layer

A method for manufacturing a two terminal or three terminal tandem solar cell comprising a silicon-based bottom solar cell and a thin-film top solar cell;

• the top solar cell being arranged on a front surface of the bottom solar cell;
• the method comprising:
• providing a silicon substrate with a front surface and a rear surface, the substrate having a first conductivity type, and carrying out a sequence of steps comprising at least:
• creating on the front surface of the silicon substrate a carrier extracting layer stack, the carrier extracting layer stack comprising at least a carrier extracting layer formed on or in the front surface of the substrate,
• creating on the rear surface of the silicon substrate a passivating coating layer comprising at least a deposition of a first AlOx layer,
• wherein the method further comprises:
• creating a sacrificial layer stack comprising at least a second AlOx layer on the carrier extracting layer stack on the front surface of the silicon substrate;
• removing the sacrificial layer stack from the carrier extracting layer stack on the front surface and thus exposing the surface of the carrier extracting layer stack free from AlOx, and
• creating one or more layers of the thin film top solar cell on the exposed carrier extracting layer stack.