One of the main challenges for the industrialization of the passivating contact approach for Si solar cells is the metallization with screen‐printed paste while maintaining the low saturation current density. Using a non‐commercial Ag paste to metallize atmospheric pressure chemical vapor deposition (APCVD) (n) poly‐Si, the metal contact formation for passivating contacts on planar and textured substrates is investigated. The paste creates deep imprints caused by silver crystallite formation at the pyramid tips of textured silicon wafers. In contrast, on planar wafers, the silver crystallite growth stops at the interface between poly‐Si and the Si wafer. Similar contact resistivities are determined by comparing textured and planar Si samples. On planar samples, a contact resistivity of 4.6(14) mΩcm2 and a saturation current density of only 141(10) fA cm−2 for the metallized contact area are demonstrated. Textured samples with a contact resistivity of 2.7(17) mΩcm2 show a higher saturation current of 480(40) fA cm−2. This etching behavior is investigated by structural and elemental analyses using scanning electron microscopy.

Passivating contacts based on polycrystalline silicon (poly-Si) on an interfacial oxide are limited by parasitic absorption, which may be reduced by incorporation of foreign elements in the poly-Si layer. In this study, the influence of carbon incorporation in the concentration range of 6.9-21.5 at% on boron-doped polycrystalline silicon carbide (poly-SiC x ) layer properties is investigated and interpreted in the context of an application as full-area passivating contact on the front side of a solar cell. For constant annealing parameters, higher carbon concentrations reduce the crystallinity of the layers. A high crystallinity in turn is confirmed to be a key parameter for the application in a solar cell as it ensures both low resistivity as well as low parasitic absorption. Low recombination current densities in the range of 7.2-12.2 fA/cm 2 are determined for all layers on interfacial oxides on planar surfaces, whereas the differences are rather related to variations in the boron concentration than to the carbon concentration or the deposition parameters. A reduction of the (p) poly-SiC x layer thickness down to 10 nm would yield a parasitic absorption current density of 1.13 ± 0.13 mA/cm 2 . Using this value and the lowest measured recombination current density, a simple model predicts a theoretical solar cell efficiency limit of 26.7 ± 0.2%.

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A new method of diode laser treatment of passivating contacts for solar cells application based on electron beam evaporated highly doped amorphous silicon (a‐Si) layers deposited on solar‐grade Czochralski wafers with SiOx tunneling layers is investigated. In a first step, an interface oxide is grown and a highly doped n‐type a‐Si layer is deposited on both sides by electron beam evaporation. In a next step, the laser treatment is applied. Two different scanning speeds of 15 and 20 mm s−1 are used. Electron backscattering diffraction and quasi‐steady‐state photo conductance measurements indicate that the a‐Si layer can be crystallized without breaking up the thin oxide layer. To determine the best parameters, the lifetime and the implied open‐circuit voltage for each laser power are measured. The first results show a fitted lifetime of 4.06 ms and an implied open‐circuit voltage up to 711 mV after a passivation step.

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