@article{dawson_lee_krim_2009, title={Tribo-Induced Melting Transition at a Sliding Asperity Contact}, volume={103}, ISSN={["0031-9007"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-70450230497&partnerID=MN8TOARS}, DOI={10.1103/physrevlett.103.205502}, abstractNote={Observation of a tribo-induced transition from solid to liquidlike behavior is reported for a scanning tunneling microscope tip in sliding contact with an indium electrode of a quartz crystal microbalance (QCM). In particular, at a sufficiently high asperity sliding speed (about 1 m/s) and/or sample temperature, a change in the contact mechanics is observed that is consistent with melting in terms of both the QCM response and an energy analysis. The results confirm that the surface, rather than bulk, melting point temperature is the more relevant quantity for tribological considerations.}, number={20}, journal={PHYSICAL REVIEW LETTERS}, author={Dawson, B. D. and Lee, S. M. and Krim, J.}, year={2009}, month={Nov} } @article{lee_seo_lucovsky_fleming_ulrich_luening_2008, title={Bulk defects in nano-crystalline and in non-crystalline HfO2-based thin film dielectrics}, volume={517}, ISSN={["0040-6090"]}, DOI={10.1016/j.tsf.2008.08.098}, abstractNote={Defect states in the form of band edge electron and hole traps in HfO2 nano-crystalline films are qualitatively different in two different length scale regimes. For grain sizes > 3–4 nm, they are discrete band edge states associated with O-atom vacancies pinned and clustered at grain boundaries, whereas in as-deposited films, and films with a physical thickness of ~ 2 nm, they are band-tail defects with a density reduced by more than an order of magnitude. Defect states in non-crystalline high Si3N4 content Hf Si oxynitride alloys are qualitatively different than those in the either regime of nano-crystallinity, but instead are similar to those in SiO2, with densities < 1011 cm− 2 contrasted with defects densities in excess of 1011 cm− 2 in films with nano-grains ~ 2 nm, and extending to > 1012 cm− 2 in films with nano-grains > 3–4 nm.}, number={1}, journal={THIN SOLID FILMS}, author={Lee, S. and Seo, H. and Lucovsky, G. and Fleming, L. B. and Ulrich, M. D. and Luening, J.}, year={2008}, month={Nov}, pages={437–440} } @article{lucovsky_lee_long_seo_luening_2009, title={Interfacial transition regions at germanium/Hf oxide based dielectric interfaces: Qualitative differences between non-crystalline Hf Si oxynitride and nanocrystalline HfO2 gate stacks}, volume={86}, ISSN={["0167-9317"]}, DOI={10.1016/j.mee.2008.05.023}, abstractNote={The contribution from a relatively low-K SiON (K ∼ 6) interfacial transition region (ITR) between Si and transition metal high-K gate dielectrics such as nanocrystalline HfO2 (K ∼ 20), and non-crystalline Hf Si oxynitride (K ∼ 10–12) places a significant limitation on equivalent oxide thickness (EOT) scaling. This limitation is equally significant for metal-oxide-semiconductor capacitors and field effect transistors, MOSCAPs and MOSFETs, respectively, fabricated on Ge substrates. This article uses a novel remote plasma processing approach to remove native Ge ITRs and bond transition metal gate dielectrics directly onto crystalline Ge substrates. Proceeding in this way we identify (i) the source of significant electron trapping at interfaces between Ge and Ge native oxide, nitride and oxynitride ITRs, and (ii) a methodology for eliminating native oxide, or nitride IRTs on Ge, and achieving direct contact between nanocrystalline HfO2 and non-crystalline high Si3N4 content Hf Si oxynitride alloys, and crystalline Ge substrates. We then combine spectroscopic studies, theory and modeling with electrical measurements to demonstrate the relative performance of qualitatively different nanocrystalline and non-crystalline gate dielectrics for MOS Ge test devices.}, number={3}, journal={MICROELECTRONIC ENGINEERING}, author={Lucovsky, G. and Lee, S. and Long, J. P. and Seo, H. and Luening, J.}, year={2009}, month={Mar}, pages={224–234} } @article{lee_long_lucovsky_luening_2008, title={Suppression of Ge-O and Ge-N bonding at Ge-HfO2 and Ge-TiO2 interfaces by deposition onto plasma-nitrided passivated Ge substrates}, volume={517}, ISSN={["0040-6090"]}, DOI={10.1016/j.tsf.2008.08.099}, abstractNote={A study of changes in nano-scale morphology of thin films of nano-crystalline transition metal (TM) elemental oxides, HfO2 and TiO2, on plasma-nitrided Ge(100) substrates, and Si(100) substrates with ultra-thin (∼ 0.8 nm) plasma-nitrided Si suboxide, SiOx, x < 2, or SiON interfacial layers is presented. Near edge X-ray absorption spectroscopy (NEXAS) has been used to determine nano-scale morphology of these films by Jahn–Teller distortion removal of band-edge d-state degeneracies. These results identify a new and novel application for NEXAS based on the resonant character of the respective O K1 and N K1 edge absorptions. Their X-ray energy difference of > 150 eV is critical for this approach.}, number={1}, journal={THIN SOLID FILMS}, author={Lee, S. and Long, J. P. and Lucovsky, G. and Luening, J.}, year={2008}, month={Nov}, pages={155–158} } @article{neeyakorn_varma_jaye_burnette_lee_nemanich_grant_krim_2007, title={Dynamics of vapor-phase organophosphates on silicon and OTS}, volume={27}, ISSN={["1573-2711"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-34547211720&partnerID=MN8TOARS}, DOI={10.1007/s11249-007-9224-y}, number={3}, journal={TRIBOLOGY LETTERS}, author={Neeyakorn, Worakarn and Varma, Manju and Jaye, Cherno and Burnette, James E. and Lee, Sang M. and Nemanich, Robert J. and Grant, Christine S. and Krim, Jacqueline}, year={2007}, month={Sep}, pages={269–276} } @article{lucovsky_luening_fleming_ulrich_rowe_seo_lee_lysaght_bersuker_2007, title={Spectroscopic studies of O-vacancy defects in transition metal oxides}, volume={18}, ISSN={["1573-482X"]}, DOI={10.1007/s10854-007-9192-x}, journal={JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS}, author={Lucovsky, G. and Luening, J. and Fleming, L. B. and Ulrich, M. D. and Rowe, J. E. and Seo, H. and Lee, S. and Lysaght, P. and Bersuker, G.}, year={2007}, month={Oct}, pages={S263–S266} } @article{chen_mamouni_zhou_schrimpf_fleetwood_galloway_lee_seo_lucovsky_jun_et al._2007, title={Total dose and bias temperature stress effects for HfSiON on Si MOS capacitors}, volume={54}, ISSN={["0018-9499"]}, DOI={10.1109/TNS.2007.910862}, abstractNote={We have performed an experimental study of the effects of ionizing radiation and bias-temperature stress on Si MOS devices with HfSiON gate dielectrics. We compare the responses of homogeneous high-SiN films and low-SiN films that contain crystalline HfO. We observe that the low-SiN films are more sensitive to ionizing radiation than the high-SiN films. In particular, the low-SiN film that includes crystalline HfO is especially vulnerable to electron trapping due to substrate injection under positive irradiation bias. Both film types exhibit reduced radiation-induced charge trapping relative to previous Hf silicates. The high-SiN film exhibits less radiation-induced net oxide-trap charge density than earlier Hf silicate films processed without nitride. We also find that these devices are relatively robust against bias-temperature stress instabilities. Consistent with the radiation response, the low-SiN devices also display elevated levels of charge trapping relative to the high-SiN devices during bias-temperature stress.}, number={6}, journal={IEEE TRANSACTIONS ON NUCLEAR SCIENCE}, author={Chen, D. K. and Mamouni, E. E. and Zhou, X. J. and Schrimpf, R. D. and Fleetwood, D. M. and Galloway, K. F. and Lee, S. and Seo, H. and Lucovsky, G. and Jun, B. and et al.}, year={2007}, month={Dec}, pages={1931–1937} } @article{abdelmaksoud_lee_padgett_irving_brenner_krim_2006, title={STM, QCM, and the windshield wiper effect: A joint theoretical-experimental study of adsorbate mobility and lubrication at high sliding rates}, volume={22}, ISSN={["0743-7463"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-34247572834&partnerID=MN8TOARS}, DOI={10.1021/la061797w}, abstractNote={We have observed that when mobile adsorbed films of benzene, tricresyl phosphate, and tertiary-butyl phenyl phosphate are present on the surface electrode of a quartz crystal microbalance (QCM), oscillation of the QCM produces clearer scanning tunneling microscope (STM) images of the electrode surface. This is in contrast to an immobile overlayer of iodobenzene, where oscillation of the QCM does not affect image quality. This observation is attributed to a "windshield wiper effect", where at MHz frequencies the tip motion maintains a region of the surface where the absorbate concentration is reduced, which leads to a clearer image. A straightforward model is presented that supports this conclusion and that provides guidelines for effective lubrication of contacts operating at MHz frequencies.}, number={23}, journal={LANGMUIR}, author={Abdelmaksoud, M. and Lee, S. M. and Padgett, C. W. and Irving, D. L. and Brenner, D. W. and Krim, J.}, year={2006}, month={Nov}, pages={9606–9609} }