Texture size control by mixing glass microparticles with alkaline solution for crystalline silicon solar cells

In this paper, we show a novel method to obtain small size textures usable in crystalline silicon (c-Si) solar cells. SiO2-based glass microparticles are mixed with a conventional KOH-based alkaline solution for making the textures. Using this mixing method, the texture size can be drastically reduced from 10 to <= 2 mu m (0.3-2 mu m). In addition, the process time and c-Si loss during the texture formation are reduced from 25 to 2 min and from 20 to 2 mu m, respectively. Thus, the process is applicable to c-Si with thickness down to 50 mu m. High-quality passivation showing the effective minority carrier lifetimes (tau(eff)) larger than several ms and effective antireflection coating are possible on the new textures. The process is named "microparticle-assisted texturing (MPAT) process", and its features are also demonstrated.