The remarkable property of Semiconductors, which makes them a basis for electronics,  is that even a small change of composition can cause drastic changes in electrical,  optical properties, and magnetic properties. The thermodynamic analysis gives one the possibility to define the equilibrium concentration of free carriers and point defects versus system parameters (growth/processing temperature, partial pressure of components, impurity concentration). That is by means of thermodynamic analysis one can find the parameters for growth or processing, which are optimal for obtaining the samples with desired properties. The thermodynamic analysis provides a deep insight into compensation processes and waves the way to overcome them.