Texturing of multicrystalline silicon with acidic wet chemical etching and plasma etching

We investigated two chemical surface texturing methods suitable for multicrystalline silicon solar cells. Etch pits were defined by lithographically opened masking layers. The etchants we used were an aqueous solution of nitric acid (HNO/sub 3/) and hydrofluoric acid (HF) for the investigation of the wet chemical approach and a parallel plate plasma reactor for dry processing. Weighted reflectance values as low as 12% without any antireflection-coating and 5% with a 105 nm thermal SiO/sub 2/ layer were achieved. The electrical properties are characterised by the determination of the emitter saturation current density. The surfaces were passivated by two different passivation schemes namely SiO/sub 2/ and a SiO/sub 2/-SiN/sub x/ stack. Solar cells on monocrystalline float zone (FZ) and multicrystalline (mc) silicon were processed to investigate the impact of the textured front surface on solar cell performance.