Electrical activity and radiation damage in ion implanted cadmium telluride

Publisher Website
Google Scholar
Abstract
Single crystals of semi-insulating cadmium telluride have been implanted with 50 keV argon ions and 100 keV indium, tellurium and bismuth ions in an attempt to reduce the resistivity of the implanted layer by the injection of free carriers. Carrier concentrations were determined from sheet resistivity and Hall measurements. The highest percentage (∽ 30%) of electrically active ions to the total number implanted was measured for a dose of 1014 indium ions/cm2 implanted into a substrate held at 200°C. Although some activity was generated by bismuth ions, tellurium and argon ions produced no measurable electrical changes. The backscattering and channelling of hetium ions was used to study the damage produced by the different ions under different implant and annealing conditions. The technique was also used to measure the bismuth atom concentration retained by samples after various annealing stages. Some of the increases in electrical activity could be correlated with reductions in radiation damage. Above annealing temperatures of 400°C however, the increases in lattice disorder and sample resistivities were probably due to thermally generated active defects and loss of the implanted ion species.