Implant isolation of both n-type InP and InGaAs by iron irradiation: effect of post-implant annealing temperature

1 MeV Fe₊ was implanted into-n-type InP and InGaS layers at different substrate temperatures, -196°C, room temperature (RT), 100°C and 200°C to obtain high resistivity regions. The sheet resistivity of the InP and InGaAs epilayers grown on semi-insulating (SI) InP substrates was measured as a function of substrates temperature and post-implantation annealing temperature (100-800°C). For InP, a maximum sheet resistivity of ∼ 1×10₇ Ω/□ was achieved for samples implanted at -196°C, RT and 100°C after annealing at 400°C. For InGaAs samples, a Maximum sheet resistivity of 1×10₇ and 2.3×10₆ Ω/□ is obtained for -196°C and RT implants respectively after annealing at 400°C. For InGaAs samples, a maximum sheet resistivity of 1×10₇ and 2.3×10₆ Ω/□ is obtained for -196°C and RT implants respectively after annealing at 50°C for 60s. In both InP and InGaAs, the isolated regions exhibit good stability to heat treatment up to 500°C for all cases irrespective of the irradiation temperature. The iron depth profile obtained by secondary ion mass spectrometry (SIMS) shows that iron does not diffuse up to an annealing temperature of 550°C in both InP and InGaAs for all implantation temperatures. These results are novel since high sheet resistivity (∼5×10₆ Ω/□) is obtained in both InP and InGaAs samples implanted at -196°C and RT, and annealed at 400°C. These data demonstrate the potential usefulness of iron implantation for isolation of InP/InGaAs based devices.