Return to list of previous seminars
| Date | Speaker | Title | Notes |
| Sept 27 | Postponed to Oct 11 | ||
| Oct 4 | Prof. Alex Yokochi OSU Chemistry |
X-ray scattering as OSU | |
| Oct 11 | Prof. Janet Tate OSU Physics |
Overview of solid state and materials physics at OSU | |
| Oct 17 Tuesday Gilbert 324 |
Prof. John B. Goodenough, University of Texas at Austin | Vibronic Superconductivity in the Copper Oxides | Pauling Lecture |
| Oct 18 Wednesday Gilbert 324 |
Prof. John B. Goodenough, University of Texas at Austin | Lithium-Insertion Compounds | Pauling Lecture |
| Oct 19 Thursday Gilbert 324 |
Prof. John B. Goodenough, University of Texas at Austin | Oxide-Ion Conductors | Pauling Lecture |
| Oct 25 | Prof David Cohen, University of Oregon Physics |
Towards an Economical Photovoltaic Technology in a Few Years: Prospects, Progress and Problems | |
| Nov 1 | Prof John L. Freeouf Oregon Graduate Institute |
Vacuum UV ellipsometry on wide band gap materials (abstract) | |
| Nov 8 | Prof. Henri Jansen OSU Physics |
Calculation of electronic band stucture | |
| Nov 15 | Prof. William Warren OSU Physics |
Electronic properties of non-crystalline materials | |
| Nov 22 | No seminar | No seminar | |
| Nov 29 Thursday Gilbert 324 |
Michael Tassotto OSU Physics |
Time-of-Flight Direct Recoil Spectrometry: Application to Liquid Surfaces and Steps toward Quantification | PhD defense |
Spectroscopic ellipsometry has become an important tool in characterizing many materials in the past few decades. Aside from the intrinsic utility of providing highly accurate measurements of the bulk dielectric response of new materials, it has proven exceptionally useful in the study of such multi-layered structures as are used for example for the gate dielectrics in CMOS technology or heterojunctions in HBT technology.
Current semiconductor technologies are driving a need for higher energy measurements, however: The scaling often predicted for CMOS technology leads to SiO2 (or ONO or NO or ...) gate thicknesses of under 2 nm, which cannot be accurately measured by conventional ellipsometry but CAN be measured accurately if the photon energy range is extended to include 9 or 10 eV photons. The same extended photon energy range permits us to establish the properties of materials as exemplified by critical points beyond the range of conventional ellipsometry B i. e., at energies above perhaps 6 eV. Such materials include the conventional high band gap semiconductors such as SiC, GaN, and the alloy series AlGaN. It also must include all possible dielectrics (AHigh _ Dielectrics@) proposed to replace SiO2, as these materials must have a sufficient barrier to both valence and conduction bands as to permit MOSFET operation.
This presentation will discuss the difficulties involved in extending the photon energy range of spectroscopic ellipsometry, and show how we overcame those problems. We shall illustrate the improvements expected in measurements of thin dielectric gate stacks. We shall show results obtained for the bulk properties of several proposed new high _ dielectrics. Finally, we shall show results for measurements for several surface treatments of SiC.