Sputtered Ge-on-Si heteroepitaxial pn junctions: Nanostructure, interface morphology and photoelectrical properties

S. M. Pietralunga, M. Feré, M. Lanata, G. Radnóczi, F. Misják, A. Lamperti, M. Martinelli, P. M. Ossi

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Ge thin films are epitaxially grown onto (1 0 0) Si substrates by DC-Pulsed Magnetron Sputtering. Relaxed single crystalline layers, with slightly misoriented domains are identified by XRD, TEM and HREM. Planar defects and threading dislocations are the relevant lattice imperfections. As-deposited Ge films are p-type without the need for intentional doping, even in the absence of grain boundaries. A pronounced flatness in the near IR absorption spectra is evident, in the absence of strong interfacial strain. This could be traced to a bandgap narrowing effect due to intragap states related to defects in the interfacial region. Photoconductive response around λ = 1.5 μm is flat and an equivalent responsivity Reff|Vbias = -1V = 1.0088 A/W at λ = 1.5 μm has been estimated. DC-Pulsed Magnetron Sputtering is therefore an attractive solution, deserving further development, to build near-infrared C-MOS compatible photodetectors, particularly suitable for low-speed applications.

Original languageEnglish
Pages (from-to)518-521
Number of pages4
JournalMicroelectronic Engineering
Volume88
Issue number4
DOIs
Publication statusPublished - Apr 2011

Fingerprint

Nanostructures
magnetron sputtering
direct current
Magnetron sputtering
Defects
defects
flatness
crystal defects
low speed
photometers
interfacial tension
grain boundaries
High resolution electron microscopy
Photodetectors
absorption spectra
transmission electron microscopy
Absorption spectra
Grain boundaries
Energy gap
thin films

Keywords

  • DC Magnetron Sputtering
  • Ge optical properties
  • Ge photodetectors
  • Ge-on-Si heteroepitaxy
  • Germanium thin films
  • TEM

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Electronic, Optical and Magnetic Materials
  • Surfaces, Coatings and Films
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics

Cite this

Sputtered Ge-on-Si heteroepitaxial pn junctions : Nanostructure, interface morphology and photoelectrical properties. / Pietralunga, S. M.; Feré, M.; Lanata, M.; Radnóczi, G.; Misják, F.; Lamperti, A.; Martinelli, M.; Ossi, P. M.

In: Microelectronic Engineering, Vol. 88, No. 4, 04.2011, p. 518-521.

Research output: Contribution to journalArticle

Pietralunga, S. M. ; Feré, M. ; Lanata, M. ; Radnóczi, G. ; Misják, F. ; Lamperti, A. ; Martinelli, M. ; Ossi, P. M. / Sputtered Ge-on-Si heteroepitaxial pn junctions : Nanostructure, interface morphology and photoelectrical properties. In: Microelectronic Engineering. 2011 ; Vol. 88, No. 4. pp. 518-521.
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