We have investigated the delta-doping of Si on GaAs vicinal surfaces on which self-organized multiatomic steps are formed during metalorganic vapor phase epitaxy (MOVPE) and the possibility of its wire-like selective incorporation into step edges to form doping quantum wires (DQWRs). We evaluated the electrical characteristics of delta-doped layers by Hall and C-V measurements and investigated their dependence on misorientation angles of GaAs vicinal substrates and doping time. The incorporation of Si is enhanced by steps. This effect is particularly important at the initial stage of delta-doping when the surface coverage of Si is not high. Our results also suggest that the doping density at multiatomic step regions is higher than at terrace regions. Therefore, it is expected that the selective wire-like incorporation of Si takes place at the step edges, and DQWRs can be realized under suitable growth conditions.

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Thickness controllability and thermal stability of Ni-InGaAs alloyed contact have been investigated with the aim of the applications to scaled metal S/D InGaAs MOSFETs. Low sheet resistance (~25 /□) Ni-InGaAs alloyed layers with the thickness as thin as 6 nm, which meets the requirement of scaled metal S/D MOSFETs (Lg < ~50 nm), have been formed by reducing evaporated Ni thickness and annealing temperature. It was found that the ultra-thin and smooth alloyed layer maintained after additional annealing at temperatures up to 250˚C. These results suggest that low temperature BEOL processes (< 250˚C) would enable us to utilize Ni-InGaAs alloyed contacts in scaled metal S/D devices.

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