Comparison of dielectric dispersion of Al2O3 and Se thin films

Abstract

Leakage mechanisms and dielectric properties of Al 2 O 3 / TiN -based metal-insulator-metal capacitors Appl. Phys. Lett. 83, 4429 (2003); 10.1063/1.1629373Electrical characteristics of metal-dielectric-metal and metal-dielectric-semiconductor structures based on electron beam evaporated Y 2 O 3 , Ta 2 O 5 and Al 2 O 3 thin film We investigate the frequency and temperature dependence of the dielectric conductivity and dielectric constant of Al 2 O 3 thin films having ionic structure and compare the results with those obtained for Se thin films having homopolar structure in the 0.1-100 kHz frequency range and in the 100-400 K temperature range. Our samples have a metal-insulator-metal configuration. Oxide-layer thickness ranges between 50 and 1550 Å for Al 2 O 3 films and 150 and 8500 Å for Se films. The existence of a minimum in the imaginary part of dielectric constant versus frequency curves for each thickness of Al 2 O 3 films leads us to conclude that two types of polarization mechanisms are dominant in different frequency regions, depending on the structure of Al 2 O 3 samples, but that only one mechanism dominates in Se samples, which do not have such minima in the imaginary part of their dielectric constant versus frequency curves.