Microstructural evolution of wet deposited nickel interfacial phases on phosphorus doped silicon surface

Abstract

Selective deposition and formation of Ni-Cu-Sn electrodes by electroless plating using an all-wet process were investigated to find a substitute for the commercial solar cells made by screen-printed Ag electrodes. Because of Ni-Cu-Sn multilayer, it is necessary to improve contact resistance at each interface using annealing process. So Nickel silicide was created by controlling the Si and Ni interface for the formation of an ohmic contact to reduce the contact resistance and improve the efficiency of solar cells. The phase transition and thermal stability of nickel silicide were analyzed in the annealing temperature range of 200–500 °C. Using electroless plated Ni, films with the thickness of 200±50 nm corresponding to the silicide phases of Ni2Si, Ni3Si2, and NiSi were identified from the thermal budget. The formation of the Ni74-Si26 silicide phase by rapid thermal processing at 250 °C was verified, and the possibility of low-temperature Ni silicidation was identified.