Growth and characterization of ultrathin Al2O3 as a passivation layer of silicon solar cells ☆

TThe properties of aluminum oxide (Al2O3) films have shown excellent performances such as remarkable passivation behaviors on both n- and p-type Si sufaces. For fabricating of Al2O3 one can use a cost saving deposition technique using atomic layer deposition (ALD). This study explores the conditions necessary for low temperature Al2O3 thin film by the ALD technique. Characteritstics of Al2O3 thin films was anlysised by variable-angle spectroscopic ellipsometer (VASE) and X-ray photoemission spectroscopy(XPS). Thickness of film was investigated depending on deposition cycles. The estimated deposition growth rates were 1.0 Å/cycle at deposition temperature of about 200oC. An Al2O3 ultra-thin film can be used as a passivation layer for Si thin film solar cells.