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β-Ga2O3 thin films were grown on the substrates of sapphire, GaN, and single crystals of β-Ga2O3, using plasma-assisted molecular beam epitaxy. By varying deposition conditions, pure-phase epitaxial β-Ga2O3 thin films were obtained, and the crystal quality of the as-grown films was optimized. A systematic characterization and a detailed analysis were performed on the films, including the nucleation process, surface morphology, crystal quality, thermal stability, as well as electrical and optical properties. Optical absorption was investigated using photothermal deflection spectroscopy, which provides detailed information about sub-gap optical absorption. Photocurrent measurements indicated a pronounced persistent photo-conductivity of β-Ga2O3. A blue-UV emission with an energy of 3–3.5 eV was observed by cathodoluminescence spectroscopy. The Fermi level position of the as-grown film was determined based on temperature-dependent electrical conductivity measurements. It is proposed that oxygen vacancies in the film form a defect band at around E c -0.8 eV that pins the Fermi level and is related to the observed photocurrent and cathodoluminescence characteristics. [ABSTRACT FROM AUTHOR]

Results from an extensive reliability characterization of HfLaSiO(N) devices, with TaN gate electrodes, are reported. It is shown that the effect of the lanthanum, initially deposited as La2O3, on a SiO2/HfSiO(N) stack, permeates the Si/SiO2 interface. A lower midgap interface state density is observed at this interface, but increased densities are seen towards the band edges. The presence of lanthanum in the dielectric results in defects in the interface layer and in the high-κ dielectric. A profile of defects in the gate stack is suggested, inferred from a combination of electrical measurements. From the location of the defects, it is argued that the reliability of lanthanum-incorporated devices is not compromised by its presence, thus enabling a reliable route to Vt tuning of n-type metal oxide semiconductor devices. [ABSTRACT FROM AUTHOR]

A leading candidate for the formation of the ultrashallow junctions needed for Lg<=45 nm devices is the combination of coimplantation of a diffusion-retarding species such as carbon with a high temperature, millisecond annealing process after the conventional spike annealing. C coimplantation with B+ for p-type metal-oxide semiconductor and P+ for n-type metal-oxide semiconductor combined with conventional spike annealing produces reduced junction depths and improved dopant activation and profile abruptness, compared to similar implants without the coimplanted species. Addition of submelt laser annealing may further improve junction activation, but the dominant impact is gate depletion reduction, in that way, delaying the need to introduce metal gates. Devices show that the overlap capacitance is reduced, consistent with the shallower junction depths and reduced lateral diffusion. The improved dopant activation manifests itself in reduced series resistance and improved Ion values. Finally, scanning spreading resistance microscopy measurements confirm the shallow junction depths and reduced lateral diffusion. [ABSTRACT FROM AUTHOR]

The pronounced high interfacial densities of states (Dit) commonly observed around the midgap energy of dielectric/GaAs interfaces are generally considered the culprit responsible for the poor electrical performance of the corresponding inversion-channel metal-oxide-semiconductor field-effect-transistors. In this work, comprehensive Dit spectra as the function of energy [Dit(E)] inside the In0.2Ga0.8As band gap were constructed by using the quasistatic capacitance-voltage and the temperature-dependent conductance method on n- and p-type ultrahigh vacuum (UHV)-Ga2O3(Gd2O3)/In0.2Ga0.8As and atomic-layer-deposited (ALD)-Al2O3/In0.2Ga0.8As metal-oxide-semiconductor capacitors. Unlike the ALD-Al2O3/In0.2Ga0.8As interface giving a Dit spectrum with a high midgap Dit peak, the UHV-Ga2O3(Gd2O3)/In0.2Ga0.8As interface shows a Dit spectrum that monotonically decreases from the valence band to the conduction band with no discernible midgap peak. [ABSTRACT FROM AUTHOR]

The effective work function (WF) of Ni3Si2 was evaluated on HfSixOy and SiO2 dielectrics. Ni3Si2 forms, in thin film Ni–Si diffusion couples with Ni to Si composition ratios between 1 and 2, after formation of a Ni2Si/NiSi stack and by its reaction at moderate thermal budgets (comparable to those used in back end processing of complementary metal-oxide-semiconductor circuits). Ni3Si2 formation limits, on the Ni-rich side, the process window for NiSi fully silicided (FUSI) gates (NiSi at interface with dielectric) to reacted Ni–Si ratios <1.5. The WF of Ni3Si2 was found to have similar values and behavior to that of NiSi, both on SiO2 (showing similar modulation with dopants) and on HfSixOy, in contrast to Ni-richer silicides such as Ni2Si and Ni31Si12 which do not exhibit significant WF modulation with dopants on SiO2 and have considerably higher WF on HfSixOy. This suggests that the chemistry and structure of the original NiSi/dielectric interface are not modified significantly by the subsequent growth of Ni3Si2 and implies that its formation may be tolerable when targeting NiSi FUSI gates, thereby expanding the process window for this application. [ABSTRACT FROM AUTHOR]

The integration of high carrier mobility materials into future CMOS generations is presently being studied in order to increase drive current capability and to decrease power consumption in future generation CMOS devices. If III-V materials are the candidates of choice for n-type channel devices, antimonide-based semiconductors present high hole mobility and could be used for p-type channel devices. In this work we first demonstrate the heteroepitaxy of fully relaxed GaSb epilayers on InP(001) substrates. In a second part, the properties of the Al2O3/GaSb interface have been studied by in situ deposition of an Al2O3 high-κ gate dielectric. The interface is abrupt without any substantial interfacial layer, and is characterized by high conduction and valence band offsets. Finally, MOS capacitors show well-behaved C-V with relatively low Dit along the bandgap, these results point out an efficient electrical passivation of the Al2O3/GaSb interface. [ABSTRACT FROM AUTHOR]