Boron Implanted, Laser Annealed p+ Emitter for n-type Interdigitated Back-contact Solar Cells

Ion implantation and laser processing technologies are very attractive for the fabrication of industrially feasible interdigitated back-contact (IBC) solar cells. In this work, p+ emitters were fabricated by boron implantation and laser annealing, and the electrical properties of emitters were investigated. An emitter sheet resistance (Rsh) in the range of 30-200 Ω/□ could be achieved by varying the implanted dose. The saturation current density (Joe) of the passivated p+ emitter with Rsh of ∼125 Ω/□ reached 95 fA/cm2, and the contact resistivity was determined to be as low as 5×10-6 Ω·cm2. Such localized p+ emitters can be applied to n-type IBC solar cells, which could avoid the high temperature thermal annealing step and related problems.