Defects and Their Annealing Properties in B+-Implanted Hg0.78Cd0.22Te Studied by Positron Annihilation

Abstract

Defects and their annealing properties in B+-implanted Hg0.78Cd0.22Te (p-type) were studied using the positron annihilation technique. For an unimplanted specimen, the major species of defects was identified to be Hg vacancies, VHg, and its concentration was estimated to be 6×1015 cm-3. For the B+-implanted specimen, a damaged region showed n-type character, and vacancy-type defects were found to be present in this region. Below the n-type layer, about 50% VHg was annihilated by the recombination between VHg and Hg atoms. After 150° C annealing, the mean size of open space of the vacancy-type defects in the n-type layer was found to decrease. At the same annealing temperature, the electron concentration in the n-type layer also decreased. Thus, an origin of donors was attributed to interstitial-type defects. The annealing temperature of the vacancy-type defects introduced by ion implantation was determined to be 300° C