Al2O3/TiO2 stack layers for effective surface passivation of crystalline silicon
Date
2013-10-16
Authors
Suh, Dongchul
Weber, Klaus J.
Choi, Duk-Yong
Journal Title
Journal ISSN
Volume Title
Publisher
American Institute of Physics
Abstract
For silicon surface passivation, we investigate stack layers consisting of a thin Al₂O₃ layer and a TiO₂capping layer deposited by means of thermal atomic layer deposition (ALD). In this work, we studied the influence of different thermal post-deposition treatments and film thickness for the activation of passivating ALD Al₂O₃ single layers and Al₂O₃/TiO₂ stack layers. Our experiments show a substantial improvement of the passivation for the Al₂O₃/TiO₂ stack layers compared to a thin single Al₂O₃ layer. For the stacks, especially with less than 10 nm Al₂O₃, a TiO₂capping layer results in a remarkably lower surface recombination. Effective fixed charge density of Al₂O₃/TiO₂ stack layers increases after TiO₂deposition and O₂ annealing. It is also demonstrated that the enhanced surface passivation can be mainly related to a remarkably low interface defect density of 1.1 × 10¹⁰ eV¯¹ cm¯², whereas post-TiO₂ heat treatment in O₂ ambience is not beneficial for the passivation of silicon, which is attributed to increasing interface defect density of stack layers.
Description
Keywords
Citation
Collections
Source
Journal of Applied Physics
Type
Journal article
Book Title
Entity type
Access Statement
License Rights
Restricted until
Downloads
File
Description
Published Version