抄録
The semi-insulating (SI) behaviors on InP have been examined by the phosphorus vapor pressure controlled wafer annealing method. Undoped InP crystals are of n type conductivity and seem to have native defects which may be related to phosphorus vacancies. Carrier concentrations of undoped InP were decreased in the range of 10^<13> to 10^<14> cm^<-3> after wafer annealing at 950℃ under the atmospheric phosphorus vapor pressure, but SI property was not obtained since there are no any native deep levels for pinning the Fermi-level . Extremely low Fe doped InP with the Fe concentration of 1.5×10^<15> cm^<-3> was converted from conductive to semi-insulating by annealing at higher than 940℃ under the phosphorus vapor pressure of 0.1 MPa. The compensation mechanism of annealed SI InP can be explained as slight amount of Fe is electrically activated by high temperature annealing and the carrier concentration of shallow donors which may be native defects such as phosphorus vacancies is decreased to the level of less than the concentration of activated Fe. Furthermore, it was found that the two-step wafer annealing is very effective to improve the uniformity of electrical electrical properties of annealed SI InP wafers.
