skip to main content

Title: Properties of the c-Si/Al{sub 2}O{sub 3} interface of ultrathin atomic layer deposited Al{sub 2}O{sub 3} layers capped by SiN{sub x} for c-Si surface passivation

This work presents a detailed study of c-Si/Al{sub 2}O{sub 3} interfaces of ultrathin Al{sub 2}O{sub 3} layers deposited with atomic layer deposition (ALD), and capped with SiN{sub x} layers deposited with plasma-enhanced chemical vapor deposition. A special focus was the characterization of the fixed charge density of these dielectric stacks and the interface defect density as a function of the Al{sub 2}O{sub 3} layer thickness for different ALD Al{sub 2}O{sub 3} deposition processes (plasma-assisted ALD and thermal ALD) and different thermal post-deposition treatments. Based on theoretical calculations with the extended Shockley–Read–Hall model for surface recombination, these interface properties were found to explain well the experimentally determined surface recombination. Thus, these interface properties provide fundamental insights into to the passivation mechanisms of these Al{sub 2}O{sub 3}/SiN{sub x} stacks, a stack system highly relevant, particularly for high efficiency silicon solar cells. Based on these findings, it was also possible to improve the surface passivation quality of stacks with thermal ALD Al{sub 2}O{sub 3} by oxidizing the c-Si surface prior to the Al{sub 2}O{sub 3} deposition.
Authors:
; ; ; ; ;  [1]
  1. Fraunhofer Institute for Solar Energy Systems (ISE), Heidenhofstrasse 2, 79110 Freiburg (Germany)
Publication Date:
OSTI Identifier:
22395455
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 23; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ALUMINIUM OXIDES; CHARGE DENSITY; CHEMICAL VAPOR DEPOSITION; DENSITY; DIELECTRIC MATERIALS; INTERFACES; LAYERS; PASSIVATION; RECOMBINATION; SILICON NITRIDES; SILICON SOLAR CELLS; SURFACES; THIN FILMS