Acceptor implantation in Fe-doped, semi-insulating indium phosphide

Abstract

Either magnesium or zinc ions have been implanted in (100)-oriented, Fe-doped, semi-insulating indium phosphide at room temperature or at 250 °C. Channeling effect measurements have revealed that the surface layer is transformed to an amorphous state by room-temperature implants with a dose of mid-1014/cm2. The implantation-induced amorphous layers disappear after 700-°C annealing, but a highly disordered region still remains if these amorphous layers exceed 0.23 μm in thickness. Carrier concentration and mobility profiles for Mg- and Zn-implanted samples have been measured by differential Hall-measurements. A dead layer, where no free carrier is detected, is formed near the implanted surface. The formation of the dead layer could be explained by the existence of the highly disordered region remaining after anneal and/or by the compensation effect due to n-type carriers introduced near the surface by room-temperature implant. It has been also shown that neither the amorphous layer nor the highly disordered region is formed in the samples where implantation is carried out at 250 °C, resulting in the annihilation of the dead layer from the carrier concentration profile.