Applications of ion implantation in III-V device technology

The use of implantation for doping and isolation of a variety of electronic and photonic III-V compound semiconductor devices will be reviewed. Complex multilayer heterostructure devices like heterojunction bipolar transistors and strained InGaAs-GaAs quantum well lasers rely on keV or MeV isolation implants, requiring thick, easily removed masks and post-implant annealing treatments to achieve high isolation resistances (≥ 10⁸ Ω cm). The effectiveness of the implant isolation technique varies as a function of the bandgap and elemental composition of the semiconductor. Devices based on GaAs, Al_xGa_1-xAs and InGaP are particularly suited to the implant isolation method. The prime dopant species for III-V materials are Si for n-type layers and Be for p-type layers, although there is increasing interest in the use of C as an acceptor because of its low diffusivity. In the latter case, a group III species must be co-implanted with the C⁺ ion to enhance the occupation of the group V lattice site.