X-ray rocking curve analysis of ion implanted mercury cadmium telluride

Abstract

Junction formation by ion implantation is a critical step in producing high quality infrared focal plane arrays in mercury cadmium telluride (MCT). We have analyzed the structural properties of MCT implanted with B at doses of 10¹⁴ and 10¹⁵ cm⁻² using double and triple crystal x-ray diffraction (DCD and TCD) to monitor the disorder and strain of the implanted region as a function of processing conditions. TCD (333) reflections show that a distinct tensile peak is produced by the high dose implant while the low dose implant shows only a low angle shoulder on the substrate peak. A preliminary association of the low angle shoulder with point defects has been made since no extended defects have been observed in the low dose range. For the high dose implant, extended defect formation has been reported and may be responsible for the tensile peak. After annealing, the low angle shoulder on the low dose implant has disappeared, while the high dose implant exhibits an increase in the tensile strain from 6.5 × 10⁻⁴ to 9.3 × 10⁻⁴ after 24 h of annealing and then decreases in tensile strain to 7.3 × 10⁻⁴ after 48 h of annealing. It is believed the changes in strain are associated with the Oswald ripening and dissolution of extended defects, which has been observed during annealing of ion implanted Si.