Random texturing process for multicrystalline silicon solar cells using plasmaless dry etching

The authors have investigated a process for randomly texturing single- and multicrystalline Si solar cells by plasmaless dry etching with a chlorine trifluoride gas. Although the reflectance of as-textured surfaces was easily reduced to below 10% at a wavelength of 600 nm in our previous study, the increase of the efficiency of the randomly textured solar cells was insufficient. This insufficient improvement was considered to be due to submicron structures formed by the dry texturing. In this study, the authors aimed to enlarge the textured structures and improve the electrical characteristics of single- and multicrystalline solar cells by modifying the texturing conditions. Surfaces with reflectance below 12% at 600 nm (corresponding to an estimated weighted reflection of 12%–13% at wavelengths between 300 and 1200 nm) were obtained, and electrical characteristics of multicrystalline solar cells were improved by using plasmaless dry texturing at a relatively high etch rate for around 1 min.