Self‐Aligned Selective Emitter Formation Using Commercial Screen‐Printed Contacts as a Plasma Etch Mask

Abstract

Selective emitter solar cells based on “screen‐printed” metallization face still several hurdles for the mass production in industry due to process complexities demanding advanced fabrication techniques and precise alignment of the final contact step. To address this issue, we present a simple and economical approach involving only a single diffusion and a plasma etching step to form the self‐aligned selective emitter (SASE) silicon solar cells. Particularly, a plasma etching step is used to reduce the thickness of homogeneous and heavily doped emitter, reducing doping concentration and thereby, increasing sheet resistance. In this paper, several distinctive characteristics of this cell concept are discussed such as; improved passivation quality of emitter by dry etching and electrical properties of screen‐printed contacts, which were used as mask during etch‐back process. Finally, a comparison of SASE solar cell with reference cells comprised of a standard homogeneous emitter is given. Since, there is no need for alignment in the selective emitter concept proposed, it appears to be an attractive solution for industrial cell fabrication.