Ion implantation-reduced diffusion length in HgCdTe^*

Laboratoire de Métallurgie Physique (UMR 6630-CNRS), Université de Poitiers, UFR Sciences, SP2MI, Bd3, Téléport 2, BP 179, 86960 Futuroscope Cedex, France

Corresponding author: Patrick.leveque@lmp.univ-poitiers.fr

Received: 7 November 1997
Revised: 22 January 1998
Accepted: 20 February 1998
Published online: 15 June 1998

Abstract

Al²⁺ (320 keV) ion implantations at room temperature for doses ranging from 3 × 10¹¹ to 3 × 10¹⁴ ions cm⁻² have been performed in p-type Hg_0.78Cd_0.22Te. The samples were analyzed by infrared reflectivity providing quantitative results on electrically active defects. A change of type of the free carriers is observed after implantation, for all doses, in a region of thickness greater than the projected range of ions. The dominant phenomena in this change of type seems to be the diffusion of Hg interstitials which takes place during implantation. From 3 × 10¹¹ to 3 × 10¹³ ions cm⁻², the diffusion length of Hg interstitials follows a classical equation with a linear dependence on the squareroot of the implantation time. For doses greater than 3 × 10¹³ ions cm⁻², Hg interstitials diffuse less efficiently. This could be due to the capture of some single interstitials by interstitial dislocation loops as observed by diffuse X-ray scattering.