Study of the hydrogenation mechanism by rapid thermal anneal of SiN:H in thin-film polycrystalline-silicon solar cells

• Published in: IEEE electron device letters 2006-03, Vol.27 (3), p.163-165
• Main Authors: Carnel, L., Dekkers, H.F.W., Gordon, I., Van Gestel, D., Van Nieuwenhuysen, K., Beaucarne, G., Poortmans, J.
• Format: Article
• Language: English
• Subjects: Applied sciences; Atomic layer deposition; Compound structure devices; Costs; Devices; Diffusion; Electronics; Energy; Exact sciences and technology; Grain boundaries; Grain size; Grains; Hydrogen; Hydrogen storage; Hydrogenation; Natural energy; Optoelectronic devices; P-n junctions; Passivation; Photovoltaic cells; Photovoltaic conversion; polycrystalline-silicon (pc-Si); Rapid thermal annealing; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Solar cells; Solar cells. Photoelectrochemical cells; Solar energy; Thin films; Transistors
• ISSN: 0741-3106; 1558-0563
• DOI: 10.1109/LED.2005.863566

A considerable cost reduction in photovoltaics could be achieved if efficient solar cells could be made from thin polycrystalline-silicon (pc-Si) films. Although hydrogen passivation of pc-Si films is crucial to obtain good solar cells, the exact mechanism of hydrogen diffusion through pc-Si layers is not yet understood. In this letter, the influence of the junction and the grain size are investigated. We find that the presence of a p-n junction acts as a barrier for hydrogen diffusion in thin-film polysilicon solar cells. Therefore, pc-Si solar cells should preferably be passivated before junction formation. Furthermore, pc-Si layers with large grains retain less hydrogen after passivation than layers with small grains. This indicates that hydrogen atoms get mainly trapped at the grain boundaries.