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Conduction at low temperature in ion‐implanted silicon
Author(s) -
Bourgoin J. C.,
Frossati G.,
Ravex A.,
Thoulouze D.,
Vandorpe M.,
Waksmann B.
Publication year - 1979
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2220920231
Subject(s) - annealing (glass) , atmospheric temperature range , condensed matter physics , conductivity , ion , thermal conduction , variable range hopping , materials science , electrical resistivity and conductivity , silicon , chemistry , thermodynamics , optoelectronics , physics , composite material , quantum mechanics , organic chemistry
Abstract The electrical conductivity in a 4 × 10 14 cm −2 , 130 keV phosphorus implanted layer is studied, after annealing, in the temperature range 4.2 K to 6 mK. The annealing (at 600°C) is such that most of the phosphorus ions become electrically active and are only partially compensated by the remaining defects. The analysis of σ versus T indicates that three different regimes of conductivity are operating, depending on the temperature range. Between 4.2 K and ≈ 100 mK the results find a reasonable interpretation in terms of three‐dimensional variable range hopping (VRH), which follows Mott's law: σ ∼ exp ( T −1/4 ). When T decreases, between ≈ 100 and ≈ 50 mK the hopping range becomes larger than the thickness of the implanted layer and a twodimensional VRH regime, in which σ ∼ exp ( T −1/3 ), takes place. At low temperature, below ≈ 50 mK, σ varies as exp ( T −1/2 ); a tentative explanation of this behaviour is proposed, in terms of correlation effects.