Role of surface fixed charge in the surface passivation of thermal atomic layer deposited Al2O3 on crystalline-Si

Abstract

In this work, surface passivation of thermal atomic layer deposited (ALD) Al2O3 films on Si has been investigated. A quantitative analysis shows that field-effect passivation based on surface fixed charge combined with chemical passivation is assumed to contribute to the passivation performance and that a low defect density is critical to passivation quality. The surface fixed negative charge, which is exponentially modulated from ∼0 cm−2 to −2×1012 cm−2 by annealing, is proposed to have arisen from the reconstruction of the interfacial SiOx layer.