Saturation of Si Activation at High Doping Levels in GaAs

Ion implantation of Si is extensively employed in the fabrication of GaAs integrated circuits as an n-type dopant. We have investigated the electrical activation of Si in GaAs with high dose (1017–1019cm−3) room temperature Si implantations in semi-insulating GaAS. A co-implantation of As with Si was used to study the influence of local stoichiometry and substrate morphology on the electrical activation of Si. A van der Pauw method was employed for electrical characterization. Our results show that the previously reported saturation in the free electron concentration at 2 × 1018 cm−3 is not altered by co-implanted As.