Interdigitated Back Passivated Contact (IBPC) Solar Cells Formed by Ion Implantation

Abstract

We describe work toward an interdigitated back passivated contact (IBPC) solar cell formed by patterned ionimplanted passivated contacts. Formation of electron and hole passivated contacts to n-type Cz wafers using a thin SiO ₂ layer and ion-implanted amorphous silicon (a-Si) is described. P and B were ion implanted into intrinsic a-Si films, forming symmetric and IBPC test structures. The recombination parameter J ₀ , as measured by a Sinton lifetime tester after thermal annealing, was J ₀ ~ 2.4 fA/cm ² for Si:P and J ₀ ~ 10 fA/cm ² for Si:B contacts. The contact resistivity for the passivated contacts was found to be 0.46 Ω·cm ² for the n-type contact and 0.04 Ω·cm ² for the p-type contact. The IBPC solar cell test structure gave 1-sun V _oc values of 682 mV and pFF = 80%. The benefits of the ion-implanted IBPC cell structure are discussed.