Silicon solar cells with chromium-copper contacts

Abstract

The authors have applied front contact metallization of chromium and copper for the processing of cost-efficient crystalline silicon solar cells. This metallization method is previously known from integrated circuit technology and its advantages are widely known: chromium has excellent adhesion properties to silicon; copper is more than twice as conductive as the bulk aluminum; and both the metals are cheap. Nevertheless, so far, chromium-copper metallization has not been applied for commercial solar cell manufacturing which might be because copper is known to affect, destructively, the charge carrier lifetimes in silicon. In this paper, the authors present the metallization process and discuss the advantages of chromium-copper metallization in the scope of fabrication of cost-efficient silicon solar cells. They have studied the essential question of the diffusion of copper into silicon diffusion parameters from the responses using a mathematical method developed in their laboratory.