Dielectric relaxation spectroscopy of single- and double-layer polyimide/SiO2 thin films

High temperature dielectric relaxation spectroscopy (DRS) experiments have been performed on MIS (metal-insulator-semiconductor), MOS (metal-oxide-semiconductor) single-layer and MIOS (metal-insulator-oxide-semiconductor) double-layer structures, where I is polyimide (PI) film (10 mu m), and O is PECVD SiO2 thin film (1.5 mu m-thick), from 200 to 350 degrees C, in the 10(-1) Hz to 10(6) Hz frequency range. In such a high temperature range and/or at low frequencies, the dielectric spectra are often influenced by interfacial dielectric relaxations such as Maxwell-Wagner-Sillars (MWS) and electrode polarization (EP). The empirical Havriliak-Negami (H-N) model is used to determine the sigma(dc) values from the effective ac dielectric response. For single- (PI) and double-layer structures (PI/SiO2), the sigma(dc) varies from 1.1x10(-10) to 5.5x10(-9) Omega(-1)cm(-1) and from 7x10(-14) to 2.3x10(-12) Omega(-1)cm(-1) between 250 and 350 degrees C, with an activation energy of the conduction phenomenon of 1.1 and 0.95 eV, respectively. The PI/SiO2 structure is suited for semiconductor device passivation applications at high temperature up to 300 degrees C.