Fe doping and preparation of semi insulating InP by wafer annealing under Fe phosphide vapor pressure

Semi-insulating (SI) InP has been industrially produced by doping Fe atoms as deep acceptors. Fe concentrations in InP are, however, largely varied from top to tail along the crystal growth axis because of impurity segregation. In the present work, we have examined the possibility of vapor phase doping for producing 50 mm diameter SI InP wafers with constant Fe concentrations by using a wafer annealing procedure. Small amount of Fe was charged with red phosphorus in ampoules in which InP wafers were annealed. It was found that the vapor phase doping is effective for Fe doping in InP. The present technology can be applied for the production of low Fe doped SI InP wafers with the same Fe concentration for all wafers from one InP ingot.