Fe Doping Activation And Defect In Semi-insulating InP

The activation of Fe doping and electrical compensation in semi-insulating InP are studied by Hall effect measurement and Fourier transform infrared absorption spectroscopy in this thesis. The surface microdefects of the InP materials are studied by Hall effect measurement and chemical etching method. The internal prerequisites of the preparation of semi-insulating InP materials which have high Fe active efficiency, good electrical properties, good uniformity and good crystal lattice integrality, have been revealed based on the experimental results. After the investigation of the microdefects and structure defects in InP, it is found that: compared with the annealing result of InP in phosphorus ambient, the annealing ambient in iron phosphide effectively improves the structure perfection and electrical uniformity. The dislocation density is almost not influenced by the thermal annealing. The impurity distribution, doping activation mechanism, and interaction between Fe atoms and point defects in Fe-doped and annealed undoped semi-insulating (SI) InP materials are compared. The substitution and activation of Fe occur mostly via an interstitial hopping mechanism in as-grown Fe-doped SI InP. However, Fe atoms aggregate around dislocations and form complex defects with vacancies. The concentration of Fe atoms at interstitial positions is very high, resulting in low activation efficiency. The activation mechanism of Fe is a kick-out substitution process in SI material obtained by annealing undoped InP in an iron phosphide ambient. Fe atoms nearly completely occupy the indium lattice sites due to the indium vacancy in the material before annealing, the formation of deep level defects is suppressed in the annealing process, this results in high Fe activation efficiency and good electrical properties of the SI-InP material.