Annealing of electron-induced defects in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>n</mml:mi></mml:math>-type germanium

Abstract

$n$-type, ${10}^{13}$ and 2 \ifmmode\times\else\texttimes\fi{} ${10}^{15}$ ${\mathrm{cm}}^{\ensuremath{-}3}$ doped germanium has been irradiated with \ensuremath{\sim} 1-MeV electrons at liquid-helium and room temperatures. With the use of transient-capacitance spectroscopy, six electron traps and one hole trap were observed following irradiation at 4 K. Their energy levels have been determined to be at ${E}_{c}\ensuremath{-}40,120,120,260,390,\mathrm{and} 530$ meV, and at ${E}_{v}+250$ meV. The isochronal annealing behavior of these traps, in addition to that of the four electron traps and of the four hole traps produced by room-temperature irradiation, has been studied in detail. Comparison of our results with previously published ones indicates that (i) the divacancy anneals around 150\ifmmode^\circ\else\textdegree\fi{}C and the $E$ center around 100\ifmmode^\circ\else\textdegree\fi{}C, (ii) the two levels at ${E}_{c}\ensuremath{-}120$ meV are associated with the germanium interstitial or complexes involving a germanium interstitial, and (iii) there appears to be a vacancy level in the range 100-200 meV from the conduction band, which anneals at \ensuremath{\sim} 100 K.