The photoluminescence mapping characteristics of semi-insulating wafers, obtained by annealing in an FeP2 ambient, were investigated. When compared with as-grown Fe-doped and undoped semi-insulating wafers prepared by annealing in pure P vapour, the FeP2-annealed semi-insulating wafer was found to exhibit a better uniformity of photoluminescence. Radial Hall measurements also showed that there was a better uniformity of the resistivity of FeP2-annealed semi-insulating wafers. Upon comparing the distribution of deep levels in the annealed wafers, as measured by optical transient current spectroscopy, it was found that the incorporation of Fe atoms into semi-insulating InP suppressed the formation of a few defects. The observed correlation implied that annealing in an FeP2 ambient made Fe atoms diffuse uniformly and occupy In sites in thesemi-insulating InP lattice. It was suggested that the annealing of undoped conductive InP in FeP2 vapour was an effective means for obtaining semi-insulating InP wafers of superior uniformity.

Photoluminescence Assessment of Undoped Semi-Insulating InP Wafers Obtained by Annealing in Iron Phosphide Vapour. H.W.Dong, Y.W.Zhao, H.P.Lu, J.H.Jiao, J.Q.Zhao, L.Y.Lin: Semiconductor Science and Technology, 2002, 17[6], 570-4