Evolution of oxide disruptions: The (W)hole story about poly-Si/c-Si passivating contacts

Different models exist describing the current transport in polycrystalline Si/SiO
_x
/crystalline Si junctions. Besides tunneling through thin oxides, transport through pinholes is discussed. We investigate the influence of annealing temperature on the structural properties of polycrystalline Si/SiO
_x
/crystalline Si interfaces and analyze the formation and evolution of holes by high resolution transmission electron microscopy in comparison to electrical results. We prove the existence of pinholes in samples with good electrical properties in agreement with the pinhole model.