Deep Level Transient Spectroscopy (DLTS) was used to study the defects introduced in Zn and Cd doped Schottky barrier diodes by 2 MeV proton irradiation. The defects H3, H4 and H5 were observed in lightly Zn doped InP, while only the defects H3 and H5 were observed in more heavily Zn doped and Cd doped InP. The defect activation energies and capture cross sections did not vary between the Zn and Cd doped InP.
The concentration of the radiation induced defects was also measured. The introduction rate of the defect H4 in the lightly Zn doped InP and the introduction rate of the defect H3 in the heavily Zn and Cd doped InP were about equal, but the introduction rate of the defect H5 varied strongly among the three types of material. The introduction rate of H5 was highest in the heavily Zn doped InP but the lowest in the heavily Cd doped InP, even though they were doped comparably. As a result, the total defect introduction rate was lowest in the highly Cd doped InP.
The results can be interpreted in terms of the models for the formation and annealing of defects, and by the different diffusion rates of Zn and Cd in InP.