Silicon Nitride Barrier Layers Mitigate Minority-Carrier Lifetime Degradation in Silicon Wafers during Simulated MBE Growth of III-V Layers

Chaomin Zhang, Laura Ding, Mathieu Boccard, Tine U. Narland, Nikolai Faleev, Stuart Bowden, Mariana Bertoni, Christiana Honsberg, Zachary Holman

Research output: Contribution to journalArticle

2 Scopus citations

Abstract

We observe a degradation of the minority-carrier lifetime in silicon substrates after a temperature cycle in a molecular beam epitaxy (MBE) chamber that is representative of the growth of III-V materials. This decrease in the lifetime is from milliseconds to microseconds, and in some cases into the sub-microsecond range. The degradation appears to be caused by thermally activated diffusion of metals from the back side of the substrate, occurring at temperatures above 500 °C. This impacts the ability to achieve high-performance monolithic III-V/Si multi-junction solar cells, since the epitaxial growth usually requires high-temperature steps (over 700 °C) for surface de-oxidation or surface reconstruction and temperatures of 400-600 °C during the epitaxial growth. We show that, through phosphorous diffusion gettering, the lifetimes of degraded wafers can be recovered to the millisecond range. Further, we demonstrate that a silicon nitride coating functions both as a diffusion barrier and as an interfacial gettering or hydrogenation agent, enabling high minority-carrier lifetimes directly out of the MBE chamber. This approach allows for the silicon minority-carrier lifetime to be maintained in the millisecond range without the need for post-growth recovery, providing a path to achieve high-efficiency III-V/Si solar cells.

Original languageEnglish (US)
Article number8625581
Pages (from-to)431-436
Number of pages6
JournalIEEE Journal of Photovoltaics
Volume9
Issue number2
DOIs
StatePublished - Mar 1 2019

Keywords

  • diffusion barrier
  • III-V/Si integration
  • minoritycarrier lifetime
  • molecular beam epitaxy (MBE)
  • SiN

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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