Uniformity of semi-insulating InP wafers obtained by Fe diffusion

As-cut semiconducting InP wafers were submitted to Fe diffusion at high tem perature. The subsequent electrical characterization showed that the wafers became semi-insulating, with resistivities well above 10(7) Omega cm and m obilities in the range of 3000-4000 cm(2)/V s. In this article a study on t he uniformity of Fe-diffused semi-insulating InP wafers is presented. The p hotoconductivity, photoluminescence and resistivity mapping showed that the short range uniformity is improved with respect to typical as-grown Fe-dop ed InP. However, sometimes the wafers exhibit long range gradients of resis tivity and luminescence intensity which are believed to be associated to te mperature gradients inside the annealing furnace. (C) 2000 American Institu te of Physics. [S0021-8979(00)02922-4].