Low-cost solar cell metallization over TCO and methods of their fabrication

摘要

Methods for fabricating busbar and finger metallization over TCO are disclosed. Rather than using expensive and relatively resistive silver paste, a high conductivity and relatively low cost copper is used. Methods for enabling the use of copper as busbar and fingers over a TCO are disclosed, providing good adhesion while preventing migration of the copper into the TCO. Also, provisions are made for easy soldering contacts to the copper busbars.

主权项

1. A method for fabricating a solar cell, comprising:
texturing a front surface of a silicon wafer; fabricating a photovoltaic structure over the front surface of the silicon wafer; fabricating a transparent conductive oxide (TCO) layer over the photovoltaic structure; and, fabricating front metallization layer in electrical contact with the TCO, by the steps of: forming a mask to delineate the metallization design; sputtering a copper seed layer over the mask; electroplating a copper layer or an alloy with 50% or more of copper over the coper seed layer; and, removing the mask; wherein the method further comprises: treating the TCO to become hydrophilic prior to fabricating the metallization layer by exposing the TCO to plasma having one of CH4/Ar, Ar/H2, or H2 after the step of forming the mask.