Patent ID: 7285720

Claim:
A solar cell, comprising: an active semiconductor structure having an active semiconductor structure front side and an active semiconductor structure back side, wherein the active semiconductor structure produces a voltage between the active semiconductor structure front side and the active semiconductor structure back side when illuminated from the active semiconductor structure front side; a back electrical contact overlying and contacting the active semiconductor structure back side; a front electrical contact overlying and contacting the active semiconductor structure front side, wherein the front electrical contact has multiple layers comprising: a titanium layer overlying and contacting the active semiconductor structure front side, a diffusion layer, wherein the diffusion layer is gold, overlying and contacting the titanium layer, wherein the titanium layer is not so thick that it prevents diffusion of the metal from the diffusion layer to the active semiconductor structure front side, a barrier layer overlying and contacting the diffusion layer, and a joining layer overlying and contacting the barrier layler; and a front electrical lead overlying and affixed to an attachment pad region of the joining layer of the front electrical contact.