Defects in Arsenic Implanted р+–n- and n+–p- Structures Based on MBE Grown CdHgTe Films

Complex studies of the defect structure of arsenic-implanted (with the energy of 190 keV) Cd x Hg 1–x Te ( x = 0.22) films grown by molecular-beam epitaxy are carried out. The investigations were performed using secondary-ion mass spectroscopy, transmission electron microscopy, optical reflection in the visible region of the spectrum, and electrical measurements. Radiation donor defects were studied in n + – p - and n + – n -structures obtained by implantation and formed on the basis of p -type and n -type materials, respectively, without activation annealing. It is shown that in the layer of the distribution of implanted ions, a layer of large extended defects with low density is formed in the near-surface region followed by a layer of smaller extended defects with larger density. A different character of accumulation of electrically active donor defects in the films with and without a protective graded-gap surface layer has been revealed. It is demonstrated that p + – n - structures are formed on the basis of n -type material upon activation of arsenic in the process of postimplantation thermal annealing with 100% activation of impurity and complete annihilation of radiation donor defects.