Abstract A theory of parametric resonance (PR) in semiconductors is constructed with an account of the interaction between electrons and volume scatterers. A new phenomenon is predicted, namely appearance of a rigid PR excitation regime. Mechanisms stabilizing the parametric instability have been analyzed. The shape of the electromagnetic wave absorption line at the PR has been found. The absorption is shown to become in some cases negative. Numerical estimates show that observation of this effect is quite feasible for modern experiment.