Double-Side Integration of High Temperature Passivated Contacts: Application to Cast-Mono Si

We report in this paper on the development of thin passivating poly-crystalline Silicon (poly-Si) on silicon oxide (SiO
_x
) stacks, with poly-Si films deposited by Low Pressure Chemical Vapor Deposition (LPCVD) and doped by Plasma Immersion Ion Implantation (PIII). Such advanced passivating contacts can be integrated, in combination with In-free TCO layers, at both the front and rear sides of high efficiency solar cells via simple fabrication processes. High iV
_oc
values close to 700 mV were obtained just after the annealing step required for the poly-Si crystallization and dopant activation. The first cell integration demonstrated photovoltaic (PV) conversion efficiencies of 21.2% for this approach. Moreover, we demonstrated that the poly-Si layers elaboration process provides efficient external gettering effects on cast-mono wafers, with bulk carrier lifetime exceeding 3 ms after the poly-Si (n
⁺
)/SiO
_x
stack formation. These results are therefore encouraging for the use of low cost, low carbon footprint Si materials, in double-side passivated contacts high efficiency cell structures.