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This letter investigates the potential of a low-temperature plasma grown silicon oxy-nitride (SiO x N y ) film for surface passivation of silicon surfaces. Using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, the film composition is studied to identify the process condition for obtaining a smooth Si-SiO x N y interface. D it in the order of ∼10 10 eV −1 cm −2 , is obtained on capping the SiO x N y with a silicon nitride (SiN v :H) film, followed by annealing at 550°C for 2 s. A surface recombination velocity of 50 cm/s is obtained for the SiO x N y -SiN v :H stack when annealed at 400°C for 2 s. The growth of an interfacial SiO x N y prior to SiN v :H deposition is found to improve the thermal stability of the silicon nitride passivation. The stack could be an interesting option with further optimization for surface passivation of n-type surfaces in mono-and multicrystalline silicon solar cells.

We have demonstrated a novel process for the fabrication of inverted pyramidal structures on silicon. The proposed technique uses no photolithography step and is instead replaced by a thin-film deposition step and thermal annealing. In this paper, inductively coupled plasma CVD (ICP-CVD) silicon nitride was used as the thin film. Blisters were formed on the silicon nitride film upon annealing at 800 • C. The silicon nitride film remaining on the surface of the wafer acts as an etch mask for the texturization process, which is carried out in an alkaline solution. It was observed that only open blisters participated in the etch process, while closed blisters were resistant to the etching solution. It was observed that the gas flow ratio, annealing time, and temperature played an important role in determining the shape, size, and areal density of the blisters. By integrating an argon plasma pretreatment in the silicon nitride deposition process, surface coverage of 51% was obtained for lower annealing temperatures of 550 • C. Upon etching the sample in an alkaline solution, a weighted average reflectance of 17.3% was obtained, indicating the potential of this process. Index Terms-Hydrogen blistering, inverted pyramidal texturing, silicon nitride. 2156-3381

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We report on phase-change material scatterers in a half-wave plate design. A simulation study shows the cross-polarization of circularly polarized light reaches close to 20% around 800 nm in the ON state. Characterization is ongoing.