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Metal-oxide-semiconductor capacitors with HfO2/1-monolayer TiO2/SiO2 stacks were examined to explore the origin of the interface dipole modulation. The capacitance–voltage (C–V) measurements exhibited that the polarity of the interface dipole layer changes depending on the gate bias. The hard X-ray photoelectron spectroscopy measurements demonstrated that an applied gate voltage induces small changes in the Ti–O chemical bonding and potential profile around the HfO2/SiO2 interface. [ABSTRACT FROM AUTHOR]

Soft x-ray-excited angle-resolved photoemission results for nitride films formed using nitrogen–hydrogen radicals on Si(100), Si(111), and Si(110) are reported. The data were obtained using synchrotron radiation, which allowed the Si 2p, N 1s, and O 1s levels to be investigated with the same probing depth. The following main results were obtained: (1) the Si3N4 film is covered with one monolayer of Si–(OH)3N. Its areal density is 15% smaller on Si(111) than on Si(100) and Si (110), (2) the Si3N4/Si interfaces on all three surfaces are compositionally abrupt. This conclusion is based on the observation that no Si atoms bonded with three N atoms and one Si atom were detected, and (3) the observation that the number of Si–H bonds at the Si3N4/Si(110) interface is 38%–53% larger than those at the Si3N4/Si(100) and Si3N4/Si(111) interfaces indicates a dependence of the interface structure on the orientation of the substrate. [ABSTRACT FROM AUTHOR]

The chemical bonding states of boron (B) in shallow P+/N junctions on Si substrates were studied by soft x-ray photoelectron spectroscopy (SXPES). This study revealed three chemical bonding states of B embedded in bulk Si. The concentration profiles of B were successfully determined by combining SXPES with step-by-step etching of Si substrates. The concentration profiles of B thus determined were in good agreement with those determined by secondary ion mass spectroscopy. The concentration profiles of holes were also determined by combining Hall measurements with the step-by-step etching of Si substrates. The concentration profiles of B having the lowest binding energy were found to agree well with the concentration profiles of holes. Therefore, B with the lowest binding energy can be assigned as activated B and those having the middle and highest binding energies can be attributed to deactivated B having chemical bonding states different from that of activated B. [ABSTRACT FROM AUTHOR]

Wet and dry oxide films-4H-SiC epitaxial (0001) C-face interfaces have been characterized by capacitance-voltage (C-V) measurements and soft x-ray excited photoemission spectroscopy (SX-PES) and hard x-ray excited photoemission spectroscopy (HX-PES) using synchrotron radiation. The interface state density for wet oxidation is much smaller than that for dry oxidation at any energy level. In the PES measurements, intermediate oxidation states such as Si1+ and Si3+ were observed. In addition, the areal densities of these states were found to be in a good correspondence with those of the interface states. The reasons for the good electrical characteristics of metal-oxide-semiconductor devices fabricated by wet oxidation are discussed in terms of the depth profiles of oxide films derived from the SX-PES and HX-PES results. [ABSTRACT FROM AUTHOR]

The soft x-ray-excited angle-resolved photoemission results for nitride films formed by using nitrogen-hydrogen radicals on Si(100), Si(111), and Si(110) are described. The abruptness of compositional transition at the [Si.sub.3][N.sub.4]/Si interface and the structure of silicon nitride films are clarified by using angle-resolved photoelectron spectroscopy.