High Fe2+/3+ trap concentration in heavily compensated implanted InP

High Fe concentrations (up to 2 x 10(19) cm(-3)) have been implanted in n-d oped InP to compensate the substrate donors. The resulting semi-insulating layers have been investigated by current-voltage (I - V) measurements and p hoto-induced current transient spectroscopy (PICTS) analyses to characteris e the Fe activation process and to study the Fe related deep levels. The ac tivation of the Fe2+/(3+) trap has been assessed by the identification of t he deep level located at E-C - 0.64 eV. The outcomes of the PICTS measureme nts have been correlated with the electrically active Fe concentration calc ulated from a numerical simulation of the I - V characteristics. We observe an increasing linear relation between the electrically active Fe concentra tion and the substrate doping density, with a maximum active Fe concentrati on as high as 2 x 10(18) cm(-3), i.e. more than an order of magnitude above the equilibrium Fe solid solubility. These data are presented and their im plications discussed.