AVS 53rd International Symposium
    Applied Surface Science Thursday Sessions
       Session AS-ThP

Paper AS-ThP36
Electron Energy Loss Function for Ultra-Thin HfO2, Al2O3 and Hf-Al-O Dielectric Films on Si(100)

Thursday, November 16, 2006, 5:30 pm, Room 3rd Floor Lobby

Session: Aspects of Applied Surface Science Poster Session
Presenter: H.J. Kang, Chungbuk National University, Korea
Authors: H. Jin, Chungbuk National University, Korea
S.K. Oh, Chungbuk National University, Korea
H.J. Kang, Chungbuk National University, Korea
S. Tougaard, University of Southern Denmark
Correspondent: Click to Email
Due to the continuous decrease in device size toward atomic dimensions, Si devices are approaching fundamental limits. To avoid quantum tunneling, high-k (high dielectric constant) gate dielectric layer is required to replace SiO2. Hf-based transition metal dielectrics have received considerable attention. In particular, high-k alloys, such as aluminate or silicate are proposed as promising gate dielectrics. Quantitative analysis of reflection electron-energy-loss spectra for ultrathin HfO2, Al2O3 and Hf-Al-O dielectric thin films on Si(100) were carried out by using Tougaard Yubero QUEELS-ε(k,Ï?)-REELS package. For HfO2, the energy loss function shows peaks in the vicinity of 10, 17, 27, 37 and 47 eV. For Al2O3, a broad peak at 22 eV with a shoulder at 14 eV and a very mild shoulder at 32 eV were observed, while for the Al2O3 doped HfO2, the peak position is similar to that of HfO2. This indicates that when Hf-Al-O film is used as a gate dielectric in CMOS transistor, its electronic structure is mainly determined by the d state of Hf. The results of a quantitative analysis successfully reproduced the trend that has been found in the experimental measurements. In addition, the inelastic mean free path (IMFP) was also calculated from the theoretical inelastic scattering cross-section. The IMFP at 300 eV was about 7.05, 9.62 and 8.48 Ã. and that at 500 eV was 11.42, 15.40 and 13.64 Ã. for HfO2, Al2O3, Hf-Al-O, respectively.