E-MRS Holds Fourth Annual Spring Meeting in Strasbourg
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J. P. Massue, Scientific Advisor, The Parliamentary Assembly of the Council of I Europe, welcomes E-MRS participants.
P. Siffert (left). Interim President of E-MRS greets Nobel Laureate Nevill Mott before plenary session begins. isms. Recent w o r k using isotopically enriched oxygen-18 has shown that, for d r y oxygen oxidation of silicon, the oxygen moves t h r o u g h the film to the interface w i t h silicon where new oxide is formed w i t h o u t exchange w i t h the oxygen already bound in oxide. Water vapor, on the other hand, moves t h r o u g h the oxide so as to exchange w i t h e x t a n t o x y g e n . Precise transport mechanisms in this case are still unclear. M o t t proposes that silanol groups formed w i t h four silicon atoms and an O H group are the transporting species. He reports that several ancilliary mechanisms and observations have been proposed involving, f o r e x a m p l e , initial oxidation in the stoichio m e t r y SiO rather than SiC>2, a strong role for electron transport in the thin film stage, the existence of a variety of amorphous SiC>2 structures, the importance of strain in oxide layers as a result of either volume change or misfit w i t h silicon, and an additional model, due to Jim Phillips of Bell Labs, which contends that the so-called amorphous SiC>2 is actually composed of 50 A crystobalite microcrystals w i t h a high degree of t w i n n i n g . M o t t then acting as session chairman introduced subsequent speakers. His talk was followed by t w o technical presentations, the first by D.T.J. Hurle concerning the mathematical relations used to describe crystal g r o w t h . H u r l e discussed the analytical modeling of crystal g r o w t h processes and pointed out the various approximations involved in approaches currently used.
His presentation concentrated on Czochralski g r o w t h of crystals in which a rotating disk is used so that not only thermal and compositional questions arise, but moment u m and kinematic viscosity factors enter. H u r l e emphasized that even when using the Onsager coefficients in a first-order perturbation expansion, nonlinearity still enters the analysis unless an additional assumption is made. The perturbation approach initially assumes that all gradients such as compositional and thermal are small. However, the additional assumption in order to maintain a linear theory actually continued
D.T.J. Hurle lectures on crystal growth at E-MRS plenary session. MRS BULLETIN, JULY/AUCUST 1986, PACE 31
involves the smallness of the change in the system from the initial global thermal equilibrium reference state. The next technical presentation was provided by J. Vanni menus, who described the concept and applications in materials science of fractals. Also included in this session were two speakers provided by the European Community (EEC) in Brussels. P. Malinverni explained ESPRIT (European Strategic Program for Research and Development in In formation Technology) and indicated its progress to be substantial. Its emphasis is on promoting precom
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