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Title: On the location and stability of charge in SiO{sub 2}/SiN{sub x} dielectric double layers used for silicon surface passivation

Dielectric double layers of thermal silicon dioxide–chemical vapour deposition (CVD) silicon nitride are found to produce excellent passivation of silicon surfaces by combining a chemical reduction of surface defect states, with a field effect reduction of carriers at the surface due to charge in the dielectrics. The charge present in such double-layers has previously been attributed to be characteristic of the interface between the two. However, experimental evidence shows this is indirect and inconclusive. This manuscript reports direct measurements that show the charge lies within 10 nm of the interface between passivating double layers of thermal silicon dioxide–plasma CVD silicon nitride. In addition, the passivation efficiency of oxide-nitride layers, deposited using optimised conditions, was found to be largely unaffected by extra charge subsequently added to the film. The passivation efficiency of textured surfaces or those produced using non-optimised deposition conditions is found to be highly dependent on the field effect component provided by extra deposited charge. Using such extra field effect component, surface recombination velocities <2 cm/s have been obtained on single oxide and oxide/nitride double layers. The extra deposited charge was found to have good long term stability when the dielectric films are submitted to a chemical treatment. By contrast,more » poor stability of the deposited charge was observed when subjected to ultraviolet radiation. These results point to the importance of the interface between dielectrics when considering how to optimise the charge present in passivating dielectric films.« less
Authors:
;  [1] ; ;  [2]
  1. Department of Materials, University of Oxford, 16 Parks Rd, OX1 3PH Oxford (United Kingdom)
  2. Fraunhofer Institute for Solar Energy Systems ISE, Heidenhofstr 2, 79110 Freiburg (Germany)
Publication Date:
OSTI Identifier:
22273639
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 14; 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; CHEMICAL VAPOR DEPOSITION; DIELECTRIC MATERIALS; HETEROJUNCTIONS; INTERFACES; PASSIVATION; PHASE STABILITY; RECOMBINATION; SILICON; SILICON NITRIDES; SILICON OXIDES; SURFACES; TEXTURE; THIN FILMS; ULTRAVIOLET RADIATION