CHARACTERISTICS AND UNIFORMITY OF GROUP-V IMPLANTED AND ANNEALED HGCDTE HETEROSTRUCTURE

This work presents characterization of implanted and annealed double l ayer planar heterostructure HgCdTe for p-on-n photovoltaic devices. Ou r observation is that compositional redistribution in the structure du ring implantation/ annealing process differs from that expected from c lassical composition gradient driven interdiffusion and impacts the pl acement of the electrical junction with respect to the metallurgical h eterointerface, which in turn affects quantum efficiency and R(0)A. Th e observed anomalous interdiffusion results in much wider cap layers w ith reduced composition difference between base and cap layer composit ion. The compositional redistribution can, however, be controlled by v arying the material structure parameters and the implant/anneal condit ions. Examples are presented for dose and implanted species variation. A model is proposed based on the fast diffusion in the irradiation in duced damage region of the ion implantation. In addition, we demonstra te spatial uniformity obtained on molecular beam epitaxy (MBE) materia l of the compositional and implanted species profile. This reflects sp atial uniformity of the ion implantation/annealing Processes and of th e MBE material characteristics.