SILVER-BISMUTH NON-CONTACT METALLIZATION PASTES FOR SILICON SOLAR CELLS

摘要

Metallization pastes for use with semiconductor devices are disclosed. The pastes contain silver particles, low-melting-point base-metal particles, organic vehicle, and optional crystallizing agents. Specific formulations have been developed that produce stratified metal films that contain less silver than conventional pastes and that have high peel strengths. Such pastes can be used to make high contact resistance metallization layers on silicon.

主权项

1. A solar cell comprising:
a silicon substrate having a front surface and a back surface; a plurality of fine grid lines on the front surface of the silicon substrate; at least one front busbar layer on the front surface of the silicon substrate, the front busbar layer in electrical contact with at least a portion of the plurality of fine grid lines; an aluminum layer on a portion of the back surface of the silicon substrate; and at least one rear tabbing layer on a portion of the back surface of the silicon substrate; wherein the rear tabbing layer comprises a stratified film that comprises at least two sublayers:
a first sublayer over the silicon substrate, the first sublayer comprising a low-melting-point base-metal; anda second sublayer over the first sublayer, the second sublayer comprising silver;wherein the second sublayer has an exterior surface, and the exterior surface is exposed to an outside environment;wherein the stratified film contains a low temperature base-metal fraction greater than 20%. wherein edges of the aluminum layer and edges of the rear tabbing overlap to form overlap regions that comprise: a solid aluminum-silicon eutectic layer on the silicon layer; a modified rear tabbing layer over the solid aluminum-silicon eutectic layer; and a portion of the aluminum layer over the modified rear tabbing layer.