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The relationship between carrier concentration and donor atomic concentration has been determined in n-type Ge films doped with P. The samples were carefully engineered to minimize non-active dopant incorporation by using specially designed P(SiH3)3 and P(GeH3)3 hydride precursors. The in

The relationship between carrier concentration and donor atomic concentration has been determined in n-type Ge films doped with P. The samples were carefully engineered to minimize non-active dopant incorporation by using specially designed P(SiH3)3 and P(GeH3)3 hydride precursors. The in situ nature of the doping and the growth at low temperatures, facilitated by the Ge3H8 and Ge4H10 Ge sources, promote the creation of ultra-low resistivity films with flat doping profiles that help reduce the errors in the concentration measurements. The results show that Ge deviates strongly from the incomplete ionization expected when the donor atomic concentration exceeds Nd  = 1017 cm-3, at which the energy separation between the donor and Fermi levels ceases to be much larger than the thermal energy. Instead, essentially full ionization is seen even at the highest doping levels beyond the solubility limit of P in Ge. The results can be explained using a model developed for silicon by Altermatt and coworkers, provided the relevant model parameter is properly scaled. The findings confirm that donor solubility and/or defect formation, not incomplete ionization, are the major factors limiting the achievement of very high carrier concentrations in n-type Ge. The commercially viable chemistry approach applied here enables fabrication of supersaturated and fully ionized prototypes with potential for broad applications in group-IV semiconductor technologies.

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Title
  • Frustrated Incomplete Donor Ionization in Ultra-Low Resistivity Germanium Films
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Date Created
2014-12-08
Resource Type
  • Text
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    Identifier
    • Digital object identifier: 10.1063/1.4903492
    • Identifier Type
      International standard serial number
      Identifier Value
      0003-6951
    • Identifier Type
      International standard serial number
      Identifier Value
      1077-3118
    Note
    • Copyright 2014 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. along with the following message: The following article appeared in 105, 23 (2014) and may be found at http://dx.doi.org/10.1063/1.4903492, opens in a new window

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    This is a suggested citation. Consult the appropriate style guide for specific citation guidelines.

    Xu, Chi, Senaratne, C. L., Kouvetakis, J., & Menendez, J. (2014). Frustrated incomplete donor ionization in ultra-low resistivity germanium films. APPLIED PHYSICS LETTERS, 105, 232103. http://dx.doi.org/10.1063/1.4903492

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