Inventors:
Douglas H. Rose - Austin TX, US
Pongsthorn Uralwong - Campbell CA, US
David D. Smith - San Jose CA, US
Assignee:
Sunpower Corporation - San Jose CA
International Classification:
C23F 1/00
US Classification:
216 24, 216 41, 216 83, 216 95, 216100, 136256
Abstract:
A solar cell is fabricated by etching one or more of its layers without substantially etching another layer of the solar cell. In one embodiment, a copper layer in the solar cell is etched without substantially etching a topmost metallic layer comprising tin. For example, an etchant comprising sulfuric acid and hydrogen peroxide may be employed to etch the copper layer selective to the tin layer. A particular example of the aforementioned etchant is a Co-Bra Etcho etchant modified to comprise about 1% by volume of sulfuric acid, about 4% by volume of phosphoric acid, and about 2% by volume of stabilized hydrogen peroxide. In one embodiment, an aluminum layer in the solar cell is etched without substantially etching the tin layer. For example, an etchant comprising potassium hydroxide may be employed to etch the aluminum layer without substantially etching the tin layer.