Proton implantation for effective electrical isolation of InP, InGaAs and GaAs: role of variable doses and implant temperature

Proton isolation of n-type InP, InGaAs and GaAs layers has been investigated. The energy of proton was chosen in such a way to create a constant level of damage throughout the conductive region in all cases. The evolution of sheet resistivity with variable implanted doses at room temperature (RT) and 200°C was studied and it is found that in the case of either InP or InGaAs, hot implants do not influence the isolation particularly for the used isolation-implant conditions. For GaAs, hot implantation controls the degree of isolation and provides better optimisation of the process. Threshold doses are also found to be dependent on sufficient damage accumulation and target temperature during implantation for GaAs samples. Possible identification of antisite defects as responsible for the isolation and their sensitivity to the enhanced dynamic annealing is also discussed.