Semi-insulating wafers which were 5 or 7.5cm in diameter were prepared by annealing (930C, 80h) undoped liquid encapsulated Czochralski material under pure P or iron

 phosphide ambients. The electrical uniformity of the annealed undoped semi-insulating wafers, together with an Fe-doped as-grown semi-insulating liquid encapsulated Czochralski InP wafer, was characterized by whole-wafer photoluminescence mapping and radial Hall measurements. Defects in the wafers were detected by photo-induced current transient spectroscopy. The results indicated that the uniformity of iron phosphide annealed wafers was much better than that of pure-P annealed wafers or as-grown Fe-doped semi-insulating InP wafers. There were fewer traps in undoped semi-insulating iron phosphide annealed wafers than in as grown Fe-doped and undoped semi-insulating pure-P annealed wafers; as revealed by photo-induced current transient spectroscopy. The good uniformity of the iron phosphide annealed wafers was related to the absence of high concentrations of pure-P thermally induced defects.

Characterization of Defects and Whole Wafer Uniformity of Annealed Undoped Semi-Insulating InP Wafers. Y.Zhao, N.Sun, H.Dong, J.Jiao, J.Zhao, T.Sun, L.Lin: Materials Science and Engineering B, 2002, 91-92, 521-4