Enhancement of the Adhesive Strength between Ag Films and Mo Substrate by Ag Implanted via Ion Beam-Assisted Deposition.

Jiajun Zhu,Yuhao Hu,Deyi Li,Meng Xu,Licai Fu,Wulin Yang,Lingping Zhou

doi:10.3390/ma11050762

Abstract

Silver-coated molybdenum is an optimum material selection to replace pure silver as solar cell interconnector. However, the low adhesive strength between Ag films and Mo substrate hinders the application of the interconnector, because it is difficult to form metallurgical bonding or compound in the film/substrate interface using conventional deposition. In order to improve the adhesion, some Ag particles were implanted into the surface of Mo substrate by ion beam-assisted deposition (IBAD) before the Ag films were deposited by magnetron sputtering deposition (MD). The objective of this work was to investigate the effect of different assisted ion beam energy on the film/substrate adhesive properties. In addition, the fundamental adhesion mechanism was illustrated. The results revealed that the adhesion between Ag films and Mo substrate could be greatly enhanced by IBAD. With the increase of the assisting ion beam energy, the adhesive strength first increased and then decreased, with the optimum adhesion being able to rise to 25.29 MPa when the energy of the assisting ion beam was 30 keV. It could be inferred that the combination of “intermixing layer” and “implanted layer” formed by the high-energy ion bombardment was the key to enhancing the adhesion between Ag films and Mo substrate effectively.

Highlights

Silver films are widely used in electrode, interconnection, decorative coating, reflector mirror, and transparent conducting films, etc., because of their excellent optical, thermal and electrical properties
Interconnection, which shows high conductivity and nice weldability, is used for interconnected materials to provide a current path between single cells for solar cell arrays in low earth orbit (LEO) spacecraft [1,2,3,4,5]
Ag films prepared by the conventional texture [34,35,36,37,38]

Summary

Introduction

Silver films are widely used in electrode, interconnection, decorative coating, reflector mirror, and transparent conducting films, etc., because of their excellent optical, thermal and electrical properties. In the presence of atomic oxygen (AO, the AO reaction rate of Ag is about 10.5 × 10−24 cm atom−1 [4]), Ag is corroded and oxidized by AO, leading to serious damage: electrical conductivity and mechanical strength losses, as well as flaking off of the material. With the development of interconnected materials, silver-coated molybdenum interconnectors have replaced the traditional Ag interconnectors [3,4,5,6,7,8,9]. 10 MPa to sustain the machining stress in the parallel gap resistance welding process and later use.

Objectives

Methods

Results