Reconstruction of lattice structure of ion-implanted near-surface regions of Hg 1 − XCd XTe epitaxial layers

Abstract

The results of X-ray, SIMS, SEM and AFM studies of near-surface regions of Hg 1 − X Cd X Te (111) and (110) structures have been presented. These structures were obtained during annealing in the vapour of main components of ISOVPE Hg 1 − X Cd X Te epitaxial layers with the surface implanted with arsenic ions. Berg-Barrett topography method and two-crystal spectrometry technique were exploited. For calculation of depth dependences of deformations and concentrations of dominating defects in the layer's near-surface regions, the Takagi-Taupin equation and generalized dynamic theory of X-ray scattering were used. From experimental SIMS analysis, the distributions of both impurity and main components of Hg 1 − X Cd X Te solid solution were determined providing more accurately the deformation profiles in near-surface regions of the structures. SIMS and SEM analyses have given evidence of abrupt gradients of content in the Hg 1 − X Cd X Te solid solution, due to small changes of thermodynamical equilibrium conditions of high-temperature annealing in the near-surface regions. These are the cause of formation of a graded-gap structure with strains in the crystal lattice. AFM studies have demonstrated that the morphology of Hg 1 − X Cd X Te structures is subjected to the influence of CdTe substrate orientation.