Influence of the Cerium Oxide Thin Film Produc-Tion Methods on the Capacitance-Voltage Charac-Teristics of the Mis Structures

Abstract

Thin films of cerium oxide are increasingly used in electronics. This interest is primarily due to the unique properties of cerium oxide: high dielectric constant; high dielectric strength; high refractive index; similarity to silicon in the crystal lattice parameter; thin film production methods are compatible with classical silicon MIS technology. The aim of this work is to establish a relationship between the electrophysical parameters of MIS structures and the technological method for producing thin dielectric films by analyzing the system of electric charges in a dielectric and at the insulator-semiconductor interface. The dependence of the electrophysical parameters of the MIS structure on the method for producing thin dielectric films is most clearly manifested in the capacitance – voltage (C – V) characteristics of these structures. This dependence is directly related to the system of electric charges in the insulator and at the insulator-semiconductor interface, which depends on the technological process of creating thin dielectric films on a semiconductor substrate.The system of charges at the insulator-semiconductor interface and near it is considered. It has been established that only the charge fixed in the dielectric influences the CV characteristics of such structures, since there are no other types of charges and / or their number is negligible. The article discusses methods for producing thin cerium oxide films that are compatible with classical silicon technology. It is shown that the capacitance-voltage characteristics (CV characteristics) of aluminum – cerium – silicon structures depend on the producing method of the dielectric film. To identify the presence of charge fixed in the dielectric, approximation of the CV characteristic was use in the voltage range corresponding to the depletion mode of the surface layer of the semiconductor. Since all experimental characteristics in the depletion mode of the surface layer of the semiconductor coincide with linear approximation, it should be assumed that the charge fixed in the dielectric is absent in the studied structures.It is established that the MIS structures obtained using the flash method are characterized by reversible changes in their flat-band voltage, due to a change in the charge value fixed in the dielectric, under the influence of external factors. The method of oxidation of a metal mirror makes it possible to obtain MIS structures with a charge fixed in a dielectric independent of external factors.Ref. 9, fig. 13.