Cadmium Telluride ion implantation specific behaviour

In order to study the damage produced as a function of both the chemical nature of the ion and the implantation energy, [111] CdTe single crystals were implanted with 150 keV Mn and 50, 100 and 200 keV P ions. Analysis of the damage was carried out by Rutherford backscattering spectrometry and ion channeling measurements using 4He beams at different energies. These measurements show that the disorder induced by ion implantation in CdTe exhibits specific features: (i) saturation of damagewithoutreachingthe amorphous state;(ii)existenceof an almostundamagednear-surfaceregion.In fact, whatever the implantation conditions, the normalized channeling yield (which is a measure of the integrated disorder) reaches the value of 0.6-0.7 at saturation and the low damaged layer depth is about 40 rtm thick. The channel- ingmeasurementsare consistentwitha previousstudyin whichthe residualdamagewasidentifiedas small-sizeddisloca- tion loops mainlylocated beyond the ion projected range Rp. These results are interpreted as indicatinga high mobilityof defects in CdTe together with a high efficiencyof the surface in their recombination process, and the role played by the dislocation-loop-inducedstress.