Selective Deposition for Interdigitated Patterns in Solar Cells

A method for creating an interdigitated pattern for a solar cell, comprising:

• providing a substrate of the solar cell, wherein a surface of the substrate includes one or more exposed regions and one or more regions covered by a patterned first passivation layer stack protected by a hard mask;
• and
• selectively depositing a second passivation layer stack comprising at least a first layer of amorphous silicon (a-Si) on the one or more exposed regions such that the first passivation layer stack and the second passivation layer stack form the interdigitated pattern,
• wherein selectively depositing the second passivation layer stack comprises:
• 1a) adding, using a plasma deposition process, a sublayer of the first layer on the hard mask and in the one or more exposed regions of the surface;
• 1b) etching, using a plasma etch process, the added sublayer on the hard mask and in the one or more exposed regions, wherein an etch rate of the added sublayer on the hard mask is higher than an etch rate of the added sublayer in the one or more exposed regions, thereby substantially removing the added sublayer from the hard mask and leaving a finite thickness of the added sublayer in the one or more exposed regions;
• and
• 1c) cleaning, using a plasma cleaning process, a surface of the remaining added sublayer in the one or more exposed regions from contaminants remaining from the plasma etch process, and adding a further sublayer of the first layer in the one or more exposed regions by repeating steps 1a) and 1b),
• wherein step 1c) is repeated until a desired thickness of the first layer in the one or more exposed regions is obtained.