Browsing by Author "Garfunkel, E."
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Item Open Access Band alignment issues in metal/dielectric stacks: a combined photoemission and inverse photoemission study of the HfO 2/Pt and HfO 2/Hf systems(Electrochemical Society, 2004) Sayan, S.; Bartynski, R.A.; Robertson J.; Suehle, J. S.; Vogel, E.; Nguyen, N. V.; Ehrstein, J.; Kopanski, J. J.; Süzer, Şefik; Holl, M. B.; Garfunkel, E.We have studied the HfO 2/Hf and HfO 2/Pt systems by photoemission and inverse photoemission spectroscopies. It is found that the "effective workfunction" of metals in multilayer structures are different than their vacuum workfunctions and are modified by their interface dipoles at the metal/high-k interface. The effective workfunction of Hf is 4.4 eV whereas that of Pt is 5.3 eV, within the range of acceptable values for PMOS and NMOS respectively.Item Unknown Band alignment issues related to HfO2/SiO2/p-Si gate stacks(American Institute of Physics, 2004-12-15) Sayan, S.; Emge, T.; Garfunkel, E.; Zhao, X.; Wielunski, L.; Bartynski, R. A.; Vanderbilt, D.; Suehle, J. S.; Süzer, Şefik; Banaszak Holl, M.The valence and conduction band densities of states for the HfO2/SiO2/Si structure are determined by soft x-ray photoemission and inverse photoemission. First principles calculations are used to help in assigning valence band maxima and conduction band minima. The energies of defect states at the band edges are estimated by comparing the theoretical and experimental results. Determinations of the local surface potentials before and after a forming gas anneal are used to help determine the possible location of the charge in the film.Item Unknown Soft x-ray photoemission studies of Hf oxidation(A I P Publishing LLC, 2003) Süzer, Şefik; Sayan, S.; Banaszak Holl, M. M.; Garfunkel, E.; Hussain, Z.; Hamdan, N. M.Charging of oxide films under x rays is an important issue that must be taken into consideration for determination of core-level binding energies as well as valence band offsets. Measurements are taken as a function of time, thickness, and annealing condition. Photoemission results show the presence of metallic Hf with the 4f7/2 binding energy of 18.16 eV, and at least one clear suboxide peak.Item Unknown Soft x-ray photoemission studies of the HfO2/SiO2/Si system(American Institute of Physics, 2002) Sayan, S.; Garfunkel, E.; Süzer, ŞefikSoft x-ray photoelectron spectroscopy with synchrotron radiation was employed to study the valence-band offsets for the HfO2/SiO 2/Si and HfO2/SiOxNy/Si systems. We obtained a valence-band offset difference of -1.05±0.1eV between HfO 2 (in HfO2/15ÅSiO2/Si) and SiO 2 (in 15 Å SiO2/Si). There is no measurable difference between the HfO2 valence-band maximum positions of the HfO2/10ÅSiOxNy/Si and HfO 2/15ÅSiO2/Si systems. © 2002 American Institute of Physics.