High-Pressure Water Vapor Heat Treatment for Enhancement of SiOx or SiNx Passivation Layers of Silicon Solar Cells

Abstract

For the production of low-cost and high-efficiency silicon solar cells, it is necessary to develop high-quality passivation techniques at low temperatures. In this study, we propose high-pressure water vapor heat treatment (HWT) as a technique for modifying the passivation layers of silicon solar cells at low temperatures. HWT at approximately 300 °C was performed on mono- and multicrystalline silicon solar cells with SiOx or SiNx passivation layers formed by plasma-enhanced chemical vapor deposition at 300 °C. After the treatment, the improvement of passivation effect was confirmed by better photovoltaic performance, electroluminescence emission intensity, and effective minority carrier lifetime. Fourier transform infrared spectrometry proved that HWT caused the formation of a Si–O–Si bonding network that terminates the silicon dangling bonds at the surface or at defects, resulting in reduced recombination.