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Title: Development of economical improved thick film solar cell contact. Quarterly report No. 1

Technical Report ·
DOI:https://doi.org/10.2172/5949645· OSTI ID:5949645

Materials were surveyed to provide candidates for an all metal electrode paste system. These consisted of a major constituent metal powder, a low melting metal powder suitable for a liquid phase sintering medium, and a powder material suitable as an etchant for silicon dioxide at sintering temperatures. By means of thermal gravimetric analysis a suitable binder was identified for low temperature fired inks. The all metal ink concept was first demonstrated with the silver system to avoid the problems of limited process windows encountered with base metal systems. A number of solid materials capable of selectively etching silicon dioxide at modest temperatures were identified. One of these, silver fluoride, has yielded very good results, wetting the silicon surface after removing a thick (3000 A) silica layer. Silver pastes containing the above materials have been prepared. A paste with silver fluoride was screened onto N-type silicon with 5..cap omega..cm resistivity. The resulting contact pads had excellent adhesion but were not electrically ohmic. Another metal ink paste, incorporating boric acid, gave substantially lower resistances; however, it would not pass a 1-hour boiling DI water immersion without losing scratch resistance.

Research Organization:
Ross (Bernd) Associates, San Diego, CA (USA)
DOE Contract Number:
NAS-7-100-955164
OSTI ID:
5949645
Report Number(s):
DOE/JPL/955164-1
Country of Publication:
United States
Language:
English