Dielectric and electrical properties of vacuum‐deposited Didymium oxide thin films

Abstract

Dielectric ancl electrical properties of sandwich structures of didyiiiiiiiii oxitle thin filtiis of several thicknesses have been investigated. The variation of capacitance and dielectric dissipation factor (Tan 6) with frequency in these filnis have heen studied. Thpse studies have shown t h a t a t room temperature, the capacitance increases with tlecrettse of frequericy and the variation is iiiore pronouncetl a t low frequencies. M'ith increase of frequency, t h e dissipation factor decreases. The increase of capacitance with decrease in frecluenc,v has been attributed to the space-charge polarisation and blocking of charge carriers a t the electrodes. The effect of thickness on capacitance and Tun S in these films huve been studied. Current-Voltage characteristics (I-V) of sandwiched Al-did.viiliuiii oxit3e-.41 structures have been studied at roo111 teiiiperature. These characteristics showpci t h a t the breaktlown voltage increases and the dielectric strength tiecreases with increaso of oxide filrii thickness. Conductivity ( a ) a t roo~ii teiiiperature have been calculated to litiderstatid the iiiechanisrii involved in the conduction proccss. These results intlicatetl t h a t the conduction i n these films is due to Schottky barriers. Breakdown I'atterrrs 01,tained in these structures by the application of tlc voltage applied across the sandwich structures have been observed with the help of Carl-Zeiss, Jena, optical tiiicroscope. The phototiiicrographs of these breakdown patterns indicate t h a t the type of breakdown in these structures niay be single-hole breakdown and is proceeded by propagating breakdown.