V. V. BOBRO, A. I. SEMENENKO*
OAS «Feodosia Instrument Engineering
Plant»
*Institute of Applied Physics NASU, Sumy
The nature of the mathematical incorrectness
of the inverse problem of ellipsometry for superthin (below 10 nm) transparent
surface films on uniform substrates is studied. It is shown that the mathematical
incorrectness in this case is caused not only by experimental errors in
measuring polarization angles, but also by an inadequate choice of the
reflecting medium model leading to inaccurate setting of substrate parameters,
which are considered to be known, and by ignoring a very thin (on the order
of 0.1 nm) transition layer on the film-substrate interface. These conclusions
are not only qualitative, but are confirmed by real experiments and numerical
simulations carried out using a special mathematical program.