The dielectric properties of Al/Si3N4/P-Si(100) MIS structure were studied from the C-V and G-V measurements in the frequency range of 1 kHz to 1 MHz and temperature range of 80-300 K. Experimental results shows that the epsilon' and epsilon" are found to decrease with increasing frequency while the value of epsilon' and epsilon" increase with increasing temperature, especially, above 160 K. As typical values, the dielectric constant epsilon' and dielectric loss epsilon" have the values of 7.49, 1.03 at 1 kHz, and only 0.9, 0.02 at 1 MHz, respectively. The ac electrical conductivity (sigma(ac)) increases with both increasing frequency and temperature. The activation energy of 24 meV was calculated from Arrhenius plot at 1 MHz. The results indicate that the interfacial polarization can be more easily occurred at low frequencies and high temperatures. (c) 2006 Elsevier B.V. All rights reserved.