We present the interface state distribution at GaAs-oxide interfaces, which consist of two large peaks around mid-gap energies, one donor-like and one acceptor-like, as well as two smaller peaks closer to the band-edge energies, which are responsible for room temperature frequency dispersion in CV-curves. The latter two peaks are strongly reduced by S-passivation treatments as well as forming gas anneals, whereas the mid-gap peaks do not get affected by such treatments. It is argued that the large midgap peaks are likely caused by physical relaxation of the surface due to stress created by the oxidation, with creation of large densities (~1013 cm-2) of As and Ga vacancies at the GaAs surface. The interface state distribution of In0.53Ga0.47As-oxide interfaces is presented as well, which consists of two donor-like peaks, one large peak close to (and partly in) the valence band edge and one smaller peak around mid-gap energies. Such an interface state distribution explains the results obtained by In0.53Ga0.47As-based nMOSFET devices. Here, again, it is argued that these two peaks are likely proper to the In0.53Ga0.47As surface itself, and due to the presence of a large density of vacancies at the surface.

As contact resistance becomes a bottle-neck in scaled CMOS devices, there is a need for source/drain epitaxy with maximum dopant concentrations and optimized contacting schemes. In this paper we discuss the use of highly doped Si:P layers for the Source/Drain formation in Si bulk FinFETs. We report on the macroscopic and microscopic properties of the Si:P layers and discuss the details of the microstructure and the manifestation of Phosphorus-Vacancy complexes at high Phosphorus concentrations. We analyze how a post-epi thermal budget like spike or laser annealing modifies the microstructure and leads to an enhanced P activation and diffusion. We also zoom in on some of the integration aspects of the Si:P layers and discuss the benefit of the high-P concentration for the contact resistivity and the final device performance.

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