The ground state energy and the binding energy of polaron excitons for
med by the minority carriers (holes) bound to electrons in the skin la
yer of a metal-insulator-semiconductor structure have been calculated.
Allowance is made for the screening of the Coulomb interaction by (a)
a gas of free carriers and (b) free carriers in an inversion channel
and for the polaron effect. Allowance for the screening of the Coulomb
interaction was found to significantly reduce the energy which binds
an exciton to the surface, which accounts for an exciton ''dead layer'
' at the surface. The Hamiltonian of electron-phonon interaction with
the surface and bulk phonons in which different screening options are
taken into account, has been derived.