Extended Compositional Range for the Synthesis of SWIR and LWIR Ge1-ySnyAlloys and Device Structures via CVD of SnH4and Ge3H8

Matthew A. Mircovich, Chi Xu, Dhruve A. Ringwala, Christian D. Poweleit, José Menéndez, John Kouvetakis

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

A chemical vapor deposition (CVD) strategy is presented for the synthesis of Ge1-ySny alloys on Si wafers with band gaps in the short-wave infrared (SWIR) range of 1.8-2.6 μm, as well as in the long-wave infrared (LWIR) at 12 μm and beyond. This broad compositional versatility is achieved by CVD reactions of Ge3H8 and SnH4 as Ge and Sn precursors, respectively. The use of conventional SnH4 instead of the previously used SnD4 is found to be critical in synthesizing alloys with Sn contents between 30 and 36%, suggesting that at very low temperatures required to grow these supersaturated alloys, the incorporation of Sn is reaction-rate-dependent. The SnD4 precursor was historically preferred to SnH4 due to its longer lifetime at room temperature. However, the difference is found not to be significant from a practical perspective, and the fact that SnH4 can be synthesized from cheap and readily available starting materials represents a significant cost reduction and portends feasibility for commercial applications. The subtle differences between SnD4 and SnH4 that may explain why alloys with Sn incorporation higher than 30% can only be achieved with the latter are discussed in detail. Optical experiments indicate that such concentrations may be sufficient to cover much of the LWIR range. Device structures containing SWIR Ge1-ySny alloys were grown with the SnH4 precursor to demonstrate its suitability as a viable Sn source. The fabricated heterostructure pin diodes display excellent structural properties and a clear rectifying behavior, providing evidence that SnH4 is a practical and versatile CVD source of Sn at all concentrations of practical interest.

Original languageEnglish (US)
Pages (from-to)3451-3460
Number of pages10
JournalACS Applied Electronic Materials
Volume3
Issue number8
DOIs
StatePublished - Aug 24 2021

Keywords

  • absorption
  • chemical vapor deposition
  • long-wave infrared range
  • stannane
  • tin-germanium alloys
  • trigermane

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrochemistry
  • Materials Chemistry

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