Molecular strategies for configurational sulfur doping of group IV semiconductors grown on Si(100) using S(MH3)2 (M = Si,Ge) delivery sources: An experimental and theoretical inquiry

John Kouvetakis, R. Favaro, G. J. Grzybowski, C. Senaratne, Jose Menendez, Andrew Chizmeshya

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3 Citations (Scopus)

Abstract

We report a new doping protocol of pure Ge films grown on Si and related Si/Sn materials based on S delivered from high reactivity hydride molecules S(MH3)2 (M = Si,Ge). The new doping strategy targets next generation semiconductor applications requiring enhanced IR optical performance as well as high-mobility field effect transistors fully integrated with silicon. To explore this paradigm, we first developed a practical and straightforward synthesis approach, which avoids the use of toxic starting materials and yields viable quantities of the title compounds. These were then used to carry out proof-of-concept low-temperature depositions of Ge/Si(100) and GeSn/Si(100) films, doped with "double donor" S atoms for the first time. These systems are characterized using standard materials science techniques via RBS, XTEM, SIMS, and XRD for structure, composition, and crystallinity, and their electrical properties are measured by the Hall method. Thermally robust dopant levels <1018 are systematically obtained using a range of process protocols, which can be further optimized for practical applications. Complementary first-principles density functional theory simulations were then used to study the stability and strain associated with the incorporation of S within the parent lattice as molecular fragments such as Ge-S-Ge, Ge-S, Si-S-Si, and Si-S derived from the S(SiH3)2 and S(GeH 3)2 molecular sources. Completely incorporated Ge-S-Ge or Ge-S units in Ge in which S resides in either substitutional (tetrahedral) or near-substitutional (3-coordinate) sites are predicted to be strongly bound (-2.36 eV and -1.49 eV, respectively) relative to interstitial S and isolated Ge vacancies, while the corresponding binding in Si-S-Si and Si-S analogs is slightly enhanced. By considering the induced lattice strain, binding energy, and the structural accommodation of molecular core bonds, plausible defect-clusters are identified and tentatively used to correlate sulfur concentrations and carrier concentrations trends. In the case of the S(GeH 3)2 grown films, a mixture of deep and shallow donor centers must be invoked to account for the observed carrier concentration enhancement.

Original languageEnglish (US)
Pages (from-to)4447-4458
Number of pages12
JournalChemistry of Materials
Volume26
Issue number15
DOIs
StatePublished - Aug 12 2014

Fingerprint

Sulfur
Doping (additives)
Semiconductor materials
Carrier concentration
Poisons
Silicon
Materials science
Secondary ion mass spectrometry
Field effect transistors
Binding energy
Hydrides
Vacancies
Density functional theory
Electric properties
Atoms
Defects
Molecules
Chemical analysis
Temperature

ASJC Scopus subject areas

  • Materials Chemistry
  • Chemical Engineering(all)
  • Chemistry(all)

Cite this

@article{3a596150e4894b37941b8bbd5ae5662b,
title = "Molecular strategies for configurational sulfur doping of group IV semiconductors grown on Si(100) using S(MH3)2 (M = Si,Ge) delivery sources: An experimental and theoretical inquiry",
abstract = "We report a new doping protocol of pure Ge films grown on Si and related Si/Sn materials based on S delivered from high reactivity hydride molecules S(MH3)2 (M = Si,Ge). The new doping strategy targets next generation semiconductor applications requiring enhanced IR optical performance as well as high-mobility field effect transistors fully integrated with silicon. To explore this paradigm, we first developed a practical and straightforward synthesis approach, which avoids the use of toxic starting materials and yields viable quantities of the title compounds. These were then used to carry out proof-of-concept low-temperature depositions of Ge/Si(100) and GeSn/Si(100) films, doped with {"}double donor{"} S atoms for the first time. These systems are characterized using standard materials science techniques via RBS, XTEM, SIMS, and XRD for structure, composition, and crystallinity, and their electrical properties are measured by the Hall method. Thermally robust dopant levels <1018 are systematically obtained using a range of process protocols, which can be further optimized for practical applications. Complementary first-principles density functional theory simulations were then used to study the stability and strain associated with the incorporation of S within the parent lattice as molecular fragments such as Ge-S-Ge, Ge-S, Si-S-Si, and Si-S derived from the S(SiH3)2 and S(GeH 3)2 molecular sources. Completely incorporated Ge-S-Ge or Ge-S units in Ge in which S resides in either substitutional (tetrahedral) or near-substitutional (3-coordinate) sites are predicted to be strongly bound (-2.36 eV and -1.49 eV, respectively) relative to interstitial S and isolated Ge vacancies, while the corresponding binding in Si-S-Si and Si-S analogs is slightly enhanced. By considering the induced lattice strain, binding energy, and the structural accommodation of molecular core bonds, plausible defect-clusters are identified and tentatively used to correlate sulfur concentrations and carrier concentrations trends. In the case of the S(GeH 3)2 grown films, a mixture of deep and shallow donor centers must be invoked to account for the observed carrier concentration enhancement.",
author = "John Kouvetakis and R. Favaro and Grzybowski, {G. J.} and C. Senaratne and Jose Menendez and Andrew Chizmeshya",
year = "2014",
month = "8",
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T1 - Molecular strategies for configurational sulfur doping of group IV semiconductors grown on Si(100) using S(MH3)2 (M = Si,Ge) delivery sources

T2 - An experimental and theoretical inquiry

AU - Kouvetakis, John

AU - Favaro, R.

AU - Grzybowski, G. J.

AU - Senaratne, C.

AU - Menendez, Jose

AU - Chizmeshya, Andrew

PY - 2014/8/12

Y1 - 2014/8/12

N2 - We report a new doping protocol of pure Ge films grown on Si and related Si/Sn materials based on S delivered from high reactivity hydride molecules S(MH3)2 (M = Si,Ge). The new doping strategy targets next generation semiconductor applications requiring enhanced IR optical performance as well as high-mobility field effect transistors fully integrated with silicon. To explore this paradigm, we first developed a practical and straightforward synthesis approach, which avoids the use of toxic starting materials and yields viable quantities of the title compounds. These were then used to carry out proof-of-concept low-temperature depositions of Ge/Si(100) and GeSn/Si(100) films, doped with "double donor" S atoms for the first time. These systems are characterized using standard materials science techniques via RBS, XTEM, SIMS, and XRD for structure, composition, and crystallinity, and their electrical properties are measured by the Hall method. Thermally robust dopant levels <1018 are systematically obtained using a range of process protocols, which can be further optimized for practical applications. Complementary first-principles density functional theory simulations were then used to study the stability and strain associated with the incorporation of S within the parent lattice as molecular fragments such as Ge-S-Ge, Ge-S, Si-S-Si, and Si-S derived from the S(SiH3)2 and S(GeH 3)2 molecular sources. Completely incorporated Ge-S-Ge or Ge-S units in Ge in which S resides in either substitutional (tetrahedral) or near-substitutional (3-coordinate) sites are predicted to be strongly bound (-2.36 eV and -1.49 eV, respectively) relative to interstitial S and isolated Ge vacancies, while the corresponding binding in Si-S-Si and Si-S analogs is slightly enhanced. By considering the induced lattice strain, binding energy, and the structural accommodation of molecular core bonds, plausible defect-clusters are identified and tentatively used to correlate sulfur concentrations and carrier concentrations trends. In the case of the S(GeH 3)2 grown films, a mixture of deep and shallow donor centers must be invoked to account for the observed carrier concentration enhancement.

AB - We report a new doping protocol of pure Ge films grown on Si and related Si/Sn materials based on S delivered from high reactivity hydride molecules S(MH3)2 (M = Si,Ge). The new doping strategy targets next generation semiconductor applications requiring enhanced IR optical performance as well as high-mobility field effect transistors fully integrated with silicon. To explore this paradigm, we first developed a practical and straightforward synthesis approach, which avoids the use of toxic starting materials and yields viable quantities of the title compounds. These were then used to carry out proof-of-concept low-temperature depositions of Ge/Si(100) and GeSn/Si(100) films, doped with "double donor" S atoms for the first time. These systems are characterized using standard materials science techniques via RBS, XTEM, SIMS, and XRD for structure, composition, and crystallinity, and their electrical properties are measured by the Hall method. Thermally robust dopant levels <1018 are systematically obtained using a range of process protocols, which can be further optimized for practical applications. Complementary first-principles density functional theory simulations were then used to study the stability and strain associated with the incorporation of S within the parent lattice as molecular fragments such as Ge-S-Ge, Ge-S, Si-S-Si, and Si-S derived from the S(SiH3)2 and S(GeH 3)2 molecular sources. Completely incorporated Ge-S-Ge or Ge-S units in Ge in which S resides in either substitutional (tetrahedral) or near-substitutional (3-coordinate) sites are predicted to be strongly bound (-2.36 eV and -1.49 eV, respectively) relative to interstitial S and isolated Ge vacancies, while the corresponding binding in Si-S-Si and Si-S analogs is slightly enhanced. By considering the induced lattice strain, binding energy, and the structural accommodation of molecular core bonds, plausible defect-clusters are identified and tentatively used to correlate sulfur concentrations and carrier concentrations trends. In the case of the S(GeH 3)2 grown films, a mixture of deep and shallow donor centers must be invoked to account for the observed carrier concentration enhancement.

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