Radiation defect formation in graded-band-gap epitaxial structures Hg_1−xCd_xTe after boron ion implantation

Abstract

This paper describes experimental and modelling results of investigations of the dynamics of accumulation and spatial distribution of electrically active radiation defects when irradiating epitaxial films of Hg 1−x Cd x Te (MCT) with different graded-band-gap layers in the surface region of the material. The films, grown by molecular-beam epitaxy (MBE), were irradiated by B ions at room temperature in the radiation dose range 10 11 -3 × 10 15 ions cm −2 with energies 20-150 keV and ion current densities from 0.001 to 0.2 µA cm −2 . The results give the differences in implantation profiles, damage accumulation and electrical properties as a function of the variable composition of the films, the implantation energy and dose in the region of introduction of the implant. Comparison of the experimental results with various models shows good agreement. Analysis of the distribution of the electrically active defects in the irradiated material shows that the variation in the composition gradient in the implantation region does not have a marked effect on the migration of primary radiation defects.

Ion milling-induced conductivity-type conversion in p-type HgCdTe MBE-grown films with graded-gap surface layers

“…In this technology, the junction forms via the release and diffusion of interstitial mercury atoms Hg I with their subsequent interaction with the defects present in the crystal [5,6]. Despite its obvious importance, the effect of the graded-gap surface layers on the process of p-n junction formation in MCT under ion/plasma treatment has so far been neglected, or discussed very little [7][8][9]. In this paper, we report on the results of the experimental study of ion millinginduced conductivity-type conversion in p-type MCT films with graded-gap surface layers, and discuss their implications for ion/plasma MCT technology.…”