Orientation Dependence of Electron Radiation Damage in InSb

The damage rate in (111)-oriented samples of InSb has been measured with the (111) face perpendicularly exposed to the incident electron beam and with the ($\overline{1}\overline{1}\overline{1}$) face similarly exposed. When the damage is separated into the portion which recovers in stage I and that which recovers in stage II, it is found that the defects which annihilate in stage II are produced at lower energies than those annihilating in stage I. Also, the defects annihilating in stage II are produced at a higher rate in samples with the (111) face exposed to the electron beam than in samples with the ($\overline{1}\overline{1}\overline{1}$) face exposed. The production rate of defects annihilating in stage I is higher when the ($\overline{1}\overline{1}\overline{1}$) face is exposed to the beam. These data are interpreted in terms of the polarity of the InSb lattice in the $〈111〉$ direction to show that the defects which annihilate in stage I are produced by the displacement of antimony atoms with a threshold displacement energy lying between 8.5 and 9.9 eV, and the defects which annihilate in stage II are produced by the displacement of indium atoms with a threshold displacement energy of about 6.4 eV. It is also possible to conclude that the likely direction of the minimum displacement energy in InSb is the $〈111〉$ direction.