Atmospherically sintered copper-base alloy application film with self-assembled barrier layer on silicon substrate for silicon photovoltaics

• Published in: Journal of alloys and compounds 2018-08, Vol.757, p.333-339
• Main Authors: Adachi, Shuichiro, Nojiri, Takeshi, Kato, Takahiko, Watanabe, Seiichi, Yoshida, Masato
• Format: Article
• Language: English
• Subjects: Atmosphere; Barrier layers; Copper; Copper alloys; Copper base alloys; Crystal structure; Crystallinity; Diffusion barriers; Diffusion layers; Electrode materials; Electrodes; Mass production; Pastes; Photovoltaic cells; Self-assembled barrier layer; Self-assembly; Silicon; Silicon substrates; Sintering; Solar cells; Structural analysis; Substrates; Tin
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2018.05.086

In this paper, we show the first production of Cu-based electrode materials including self-assembled barrier layers which can prevent Cu-Si inter-diffusion during sintering and are expected to be applicable to crystalline Si photovoltaics. The characteristics of electrodes produced by mixed Cu-P/Sn pastes at various compositions were evaluated. Electrodes sintered in an atmospheric environment showed electrical resistivity of below 1 × 10−4 Ω・cm. In addition, the formation of compounds such as Cu3Si at the Si surface was prevented with a Sn particle ratio ranging between 20 and 60 wt%. The structural analysis revealed that the electrode included not only a Cu-Sn IMCs network but also a self-assembled Sn-P-O glass phase between the Cu-Sn IMCs network and the Si substrate, capable of forming a barrier layer to prevent Cu-Si inter-diffusion. These results may enable the widespread use of atmospherically sintered Cu-based electrode for the mass production of next-generation crystalline Si solar cells. Subsequently, the manner in which the Sn-P-O glasses were formed was discussed using a thermos-dynamical approach. [Display omitted] •Cu-based electrodes applicable to the forming on Si substrate were reported.•The electrode paste includes Cu-P alloy and Sn particles.•Cu-P + Sn electrodes had no Cu-Si compounds at the Si surface.•A self-assembled Sn-P-O glass phase can prevent Cu-Si inter-diffusion.