Charge characteristics of MOS structure with thermal SiO2 films doped with phosphorus under high-field electron injection

Abstract

The processes of changing the charge state of metal–oxide–semiconductor (MOS) structures that contain a multilayer gate dielectric on the basis of a thermal SiO₂ film doped with phosphorus under the influence of high-field electron injection are investigated. It is determined that a negative charge accumulating in a thin phosphosilicate glass (PSG) film of MOS structures containing a SiO₂–PSG two-layer gate dielectric under high-field tunneling injection of electrons can be used for the correction of the threshold voltage, for the enhancement of the charge stability, and for an increase in the breakdown voltage of devices with MOS structure. It is shown that the density of electron traps increases with an increase in the thickness of the PSG film containing them, while their capture cross section remains unchanged. The method for the modification of the electrophysical characteristics of MOS structures by the high-field tunneling injection of electrons into a dielectric under a controlled current load is proposed. The method allows one to control changes in the parameters of MOS structures directly in the process of their modification. It is established that a MOS structure with a high thermal field stability can be obtained by its annealing at 200°C after the modification of its charge state by the electron injection.