Enhanced activation of Zn-implanted GaAs

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Abstract
Limitations on high level doping have been investigated for implanted Zn in GaAs. Fast diffusive redistribution during the annealing of heavy dose Zn implants generally leads to broader doped layers of lesser concentrations. Though such a redistribution can be prevented by short duration annealing of ∼1 s, this alone is not sufficient to increase the peak concentration. Significantly better activation can be obtained if an excess of As is also provided. It is found that coimplanting As with Zn in addition to short duration annealing provides layers with peak doping concentrations increased to levels approaching 1020 cm−3. Doping enhancement related to encapsulation and the outdiffusion of Ga into SiO2 has also been observed.