Comparison of diamond wire cut and silicon carbide slurry processed silicon wafer surfaces after acidic texturisation

Our work focuses on the acidic etching of silicon wafers, cut via diamond wire (DW) or silicon carbide slurry process (SP). The DW and SP as-cut wafer surface structures have a significant impact on the evolution of the two resultant and different etched morphologies. The time-dependent development of the surface morphology for mono- and multi-crystalline wafers is compared and analyzed via etch rates, reflectivity measurements and confocal microscopy. The as-cut structure of the differently sawn wafers defines a template where the etch attack preferentially occurs and predetermines the texturisation of the etched surface. Based on the experimental results it is possible to lower the reflectivity of the SP-sawn wafers by varying the acidic mixture. On the contrary, the DW-sawn wafers obtain only a small enlargement of the folded surface area during acidic texturisation and no influence of different acidic etch solutions on the reflectivity values was found. To create homogeneously texturized DW-sawn wafers of low reflectivity, an adaptation of the sawing process as well as the development of new etchants and new etch conditions is necessary.