AbstractThe semiconductor is considered as a plasma of electrons, donors and occupied acceptors in a homogeneous medium interacting by Coulomb's law. The mass action law for the ionization equilibrium of electrons and donors is formulated taking into account the interaction of the charges. The lowering of the ionization energy is calculated using the quantum statistical method of binary density matrices. By comparision with the experimental results of Debye and Conwell for the lowering of the ionization energy good agreement between theory and experiment was found. The limit of stability of the semiconductor state is investigated.