Electrical conduction in annealed semi-insulating InP

Variable-temperature current-voltage has been used to study the conduction properties of Fe-doped semi-insulating (SI) InP in the as-grown and anneale d states. It is found that the trap-filling (TF) process disappears gradual ly with lengthening of annealing time. This phenomenon is explained by the decrease of the concentration of the empty Fe deep level (Fe3+) that is cau sed by the thermally induced donor defect formation. The TF process cannot be observed in annealed undoped and long-time annealed Fe-doped SI InP mate rial. The breakdown field of annealed undoped and Fe-doped SI InP is much l ower than that of as-grown Fe-doped InP material. The breakdown field decre ases with decreasing of temperature indicating an impact ionization process . This breakdown behavior is also in agreement with the fact that the conce ntration of the empty deep level in annealed InP is lowered. (C) 2000 Ameri can Institute of Physics. [S0021-8979(00)04108-6].