Charge distribution in a MIS insulator from spectral characteristics of photoemission current

The field dependence of photoemission currents in a MIS structure was deriv ed for the case when the space charge is randomly distributed over the insu lating layer. It was found analytically that the position of the top of the potential barrier for electrons photoinjected from the gate into the insul ator is defined by the derivative of this barrier with respect to the exter nal field strength. A method for correctly determining the space charge pro file in a MIS insulator is suggested. The profile is derived from a family of spectral characteristics taken at different gate voltages. The method is especially suitable for profiling the negative charge in MIS insulators. ( C) 2001 MAIK "Nauka/Interperiodica".