IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Dielectrics Monday Sessions
       Session DI1-MoP

Paper DI1-MoP19
Thermal Decompostion Mechanisms of (Ba,Sr)TiO@sub 3@ Film Precursors

Monday, October 29, 2001, 5:30 pm, Room 134/135

Session: High K Dielectrics Poster Session
Presenter: J.P. Senosiain, Stanford University
Authors: J.P. Senosiain, Stanford University
C.B. Musgrave, Stanford University
Correspondent: Click to Email
Next-generation memory devices will require high-permittivity dielectric materials able to handle sufficient charge as the dimensions of memory cells continue to scale down. Barium strontium titanate (BSTO) is a strong candidate for such applications, with a dielectric constant many times higher than that of the presently used silicon oxy-nitrides. To grow BSTO thin films effectively, a basic understanding of the precursor chemistry and deposition mechanism is needed, yet the literature in this areas is quite scarce. We have employed Density Functional Theory (DFT) and pseudopotential basis sets to study the thermal decomposition mechanisms of the @beta@-diketonate precursors: Ba(thd)@sub 2@, Sr(thd)@sub 2@ and Ti(OH)@sub 2@(thd)@sub 2@. In all these species, we find the metal-oxygen bond to be the weakest and thus the first to be broken. The cleavage of a second metal-oxygen bond leads to considerable geometric rearrangement and is energetically favourable. This is followed by the detachment of tert-butyl radicals and possible ring-closing reactions. Other decomposition channels, as well as their implications to the deposition process, are discussed in terms of their thermochemistry.