Numerous challenges remain unresolved to achieve photovoltaic conversion efficiency above 30% for mainstream application by utilization of PK/Si tandem solar cells. For a 2-Terminal (2T) tandem configuration, it is necessary to adapt the perovskite (PK) top-cell to a crystalline silicon (c-Si) bottom-cell, in terms of size and fabrication processes. One adjustment concerns the ESL deposition. Solvent-based processes mainly employed in single-junction PK cells are not appropriate for the top-cell integration in the tandem case, where the c-Si bottom-cell is a large and textured substrate. Among other possibilities, Atomic Layer Deposition (ALD) seems more suitable for such ESL deposition. To this day, few studies report the use of ALD-grown tin oxide (SnO2) as an ESL in NIP PK top-cell for 2T tandems. Aiming at a better understanding on how ESL-PK interaction relates to device performances, the present work investigates SnO2 thin films, then PK films properties and, finally, analyses integration of ALD-grown SnO2 as ESL in single-junction PK cells.