Ultrathin SiO2/Al2O3 passivation for silicon heterojunctions using rapid thermal annealing

Sangpyeong Kim, Andre Augusto, Stuart G. Bowden, Christiana B. Honsbeg

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

In this manuscript we study the surface passivation properties of ultrathin Al2O3 in silicon heterojunctions. The Al2O3 layer needs to be thin enough (<1.2nm) to enable carrier collection through the passivation layer. Previous work on Al2O3 shows that thicknesses below 10nm do not provide adequate surface passivation. In this work, we combine 0.8 nm of Al2O3 with 1nm of SiO2 to improve the passivation properties of the thin Al2O3. The SiO2 helps to improve the chemical passivation by increasing the storage capacity of hydrogen with Al2O3, and the overall negative fixed charge of the SiO2/Al2O3 stack. Additionally, we have optimized the rapid thermal annealing in forming gas environment to activate the Al2O3 in the SiO2/Al2O3 stack. To further increase the hydrogen in the films we deposited n-a-Si:H film before the annealing step. Effective minority-carrier lifetimes of 5 ms and implied open-circuit voltages of 723 mV were accomplished.

Original languageEnglish (US)
Title of host publication2020 47th IEEE Photovoltaic Specialists Conference, PVSC 2020
PublisherInstitute of Electrical and Electronics Engineers Inc.
Pages2104-2108
Number of pages5
ISBN (Electronic)9781728161150
DOIs
StatePublished - Jun 14 2020
Event47th IEEE Photovoltaic Specialists Conference, PVSC 2020 - Calgary, Canada
Duration: Jun 15 2020Aug 21 2020

Publication series

NameConference Record of the IEEE Photovoltaic Specialists Conference
Volume2020-June
ISSN (Print)0160-8371

Conference

Conference47th IEEE Photovoltaic Specialists Conference, PVSC 2020
CountryCanada
CityCalgary
Period6/15/208/21/20

Keywords

  • Al2O3 passivation
  • Rapid thermal annealing
  • SiO2 inter layer

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Industrial and Manufacturing Engineering
  • Electrical and Electronic Engineering

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