Solid body and liquid superficial structure study by ellipsometry considering mathematical inverse problem incorrectness. Part 4. Special features of the process of minimization of the functional of reverse task for semiconductors with transparent ultra thin films

Minimization functional procedure of the reverse task in the space of all parameters of the reflecting system (the semi-conductor substrate-transparent ultra-thin film) was developed. This allows to solve a number of problems. Rules of choice of initial significances of refractive index and quotient of absorption of the substrate for the first step of a method of consecutive approaching in the decision of an inverse problem become physically substantiated. Now due to the reliability of the developed procedure these initial values are naturally set on the point of the absolute minimum of the functional in complete space of parameters of the reflecting system. This ensures coordination of the initial values with the parameters of the film defined in the course of finding of an absolute minimum of the functional. At the same time it also means a complete coordination with the types of experimental errors. Definition of types of errors was added by new conditions on parameters value in the point of an absolute minimum functional. This allowed more precise classification of experimental errors. In this connection there is a possibility to define a degree of manifestation of mathematical incorrectness of reverse task depending on the size and type of experimental errors.