Industrial Czochralski silicon (Cz-Si) photovoltaic (PV) efficiencies have routinely reached >20% with the passivated emitter rear cell (PERC) design. Nanostructuring silicon (black-Si) by dry-etching decreases surface reflectance, allows diamond saw wafering, enhances metal gettering, and may prevent power conversion efficiency degradation under light exposure. Black-Si allows a potential for >20% PERC cells using cheaper multicrystalline silicon (mc-Si) materials, although dry-etching is widely considered too expensive for industrial application. This study analyzes this economic potential by comparing costs of standard texturized Cz-Si and black mc-Si PERC cells. Manufacturing sequences are divided into steps, and costs per unit power are individually calculated for all different steps. Baseline costs for each step are calculated and a sensitivity analysis run for a theoretical 1 GW/year manufacturing plant, combining data from literature and industry. The results show an increase in the overall cell processing costs between 15.8% and 25.1% due to the combination of black-Si etching and passivation by double-sided atomic layer deposition. Despite this increase, the cost per unit power of the overall PERC cell drops by 10.8%. This is a significant cost saving and thus energy policies are reviewed to overcome challenges to accelerating deployment of black mc-Si PERC across the PV industry.

In this work, we report the successful growth of high-quality SiO2 films by low-temperature plasma-enhanced atomic layer deposition using an oxidant which is compatible with moisture/oxygen sensitive materials. The SiO2 films were grown at 90 °C using CO2 and Bis(tertiary-butylamino)silane as process precursors. Growth, chemical composition, density, optical properties, and residual stress of SiO2 films were investigated. SiO2 films having a saturated growth-per-cycle of ~ 1.15 Å/cycle showed a density of ~ 2.1 g/cm3, a refractive index of ~ 1.46 at a wavelength of 632 nm, and a low tensile residual stress of ~ 30 MPa. Furthermore, the films showed low impurity levels with bulk concentrations of ~ 2.4 and ~ 0.17 at. % for hydrogen and nitrogen, respectively, whereas the carbon content was found to be below the measurement limit of time-of-flight elastic recoil detection analysis. These results demonstrate that CO2 is a promising oxidizing precursor for moisture/oxygen sensitive materials related plasma-enhanced atomic layer deposition processes.