AVS 53rd International Symposium
    Thin Film Friday Sessions
       Session TF+EM-FrM

Paper TF+EM-FrM8
In Situ ATR - FTIR Spectroscopy of Hf (IV) Tert Butoxide and Tetrakis Ethyl Methyl Amino Hf Adsorption on Si (100), Si (111) and Ge

Friday, November 17, 2006, 10:20 am, Room 2022

Session: In-Situ/Ex-Situ & Real-Time Monitoring and Characterization
Presenter: K. Li, The University of Alabama
Authors: K. Li, The University of Alabama
S. Dubey, The University of Alabama
T.M. Klein, The University of Alabama
Correspondent: Click to Email
Hafnium oxide ultra thin films on Si are being developed to replace thermally grown SiO2 gates in CMOS devices. In this work, a specially designed attenuated total reflectance - fourier transform infra-red spectroscopy (ATR-FTIR) reaction cell has been developed to observe chemisorption of hafnium (IV) t-butoxide (HtB) and tetrakis ethyl methyl amino hafnium (TEMAH), onto a Si (100), Si (111) and Ge ATR crystals heated up to 250°C and under 1 torr of vacuum allowing the observation of initial reaction pathways in real time. Chemisorption spectra were compared to spectra of the liquid precursor and to spectra generated by density functional theory (DFT) calculations of liquid, monodentate and bidentate adsorbed precursors. Asymmetric stretching modes located at 1017 cm-1 and 1250cm-1 present in the chemisorbed spectra but not in the liquid spectra of HtB indicate that the adsorbed hafnium containing group is prevalent as a bidentate ligand on Si (111). Surface concentration of the chemisorbed species was dependant on the substrate temperature and precursor partial pressure allowing for determination of heats of adsorption of the t-butyl groups, which is 26.5 kJ/mol for HtB on Si (111).