Dielectric Relaxation Effects in a Metal-Oxide-Plasma Capacitor

摘要

Measurements of k*C sub g, the complex dielectric constant k* times the geometrical capacity C sub g, of a metal-oxide-plasma capacitor have shown that k* exhibits dispersion in the audio frequency range. A series of dielectric-relaxation spectra has been obtained for Al2O3 layers (anodized) by varying the plasma density. The dependence of the spectra on plasma density and oxide thickness is indicative of Maxwell-Wagner behavior. A Cole-Cole representation of the data shows a broadening of the dispersion toward low frequency, with a secondary dispersion appearing at low frequency. The main dispersion can be described by an empirical dispersion formula which represents an asymmetrical distribution of relaxation processes. There are indications that the secondary dispersion is the result of the migration of ions injected from the plasma into pores in the oxide coating. (Author)