Study of electrical properties in mixed oxide sandwich structures

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.

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

Kumar

Rao

1985

Effect of Electric Field on Dielectric Properties of SnO₂ Sb₂O₃ and their Mixed Thin Films

Kumar

Rao

et al. 1991

Thin films of various thicknesses in the MIM structure have been prepared from the the powders of SnO,, Sb,O, and (SnO, + SbzO3) of high purity by the thermal evaporation technique in a vacuum ofTorr. Dielectric properties of SnO,, Sb,O,, and their mixed thin films have been studied with ac and dc electric fields and frequency. Capacitance and loss tangent are almost independent on dc voltage upto 1.0 V for SnO,, 10.0 V for Sb,03 and 2.5 V for mixed films. These capacitors become unstable at 1.0 V for SnO, films and 2.5 V for mixed films. For higher film thicknesses the decay in these films starts at higher voltages. Capacitance and loss tangent increases with applied ac voltage in SnO,, Sb,O,, and their mixed films. A comparison of the capacitance values of SnO,, Sb,03, and their mixed films showed that the capacitance values are less in Sb,03 as compared to SnO, films. In mixed films the capacitance is greater than the constituent films. These studies have shown that Sb,03 films are found to be more stable compared to SnO, and their mixed films for ac and dc voltages. The results thus obtained on SnO,, Sb,O,, and their films are presented and discussed.

Dielectric Properties of Tin Oxide Thin Film Capacitors

Kumar¹,

Rao²

1991

Thin films of several thicknesses in the form of MIM structures are prepared from the powders of tin oxide (SnO,) by thermal evaporation technique in a vacuum of Torr. The dielectric properties of tin oxide film capacitors have been studied with temperatures varying from 77 to 400 K and also with frequency. At 77 K the values of capacitance and loss tangent are small for these films. With increasing temperature the values of capacitance and loss tangent increase. The capacitancetemperature plots show peak values of capacitance at 345 K for 1 kHz, 350 K for 2 kHz, 360 K for 5 kHz and 368 K for 10 kHz. These peak values of capacitance can be eliminated by repeated heating and cooling of the structures. The activation energy for the migration of charge carriers is calculated for tin oxide films and is found to be 0.13 eV. The results obtained on the dielectric properties of tin oxide thin films are presented and discussed.