Application of the Gevers–Du Pre Theory of Amorphous Dielectrics

Abstract

A review is given of the Gevers–du Pre theory of amorphous dielectrics and its findings are examined for applicability to amorphous films of silicon monoxide (SiO). In the context of the theory amorphous dielectrics are defined as those insulators having irregular structures, a wide range of activation energies, and a broad spectrum of relaxation times. Inasmuch as polycrystalline film dielectrics display a distribution of relaxation times, the Gevers–du Pre theory should apply to films of SiO and many other dielectrics. For the present study, SiO was deposited onto boro-silicate glass substrates at rates ranging from 54 to 133 Å/min. The values of the temperature coefficient of capacitance (TCC) showed a strong dependence upon the deposition rate, varying from −23 to +300 ppm/°C. The negative values were obtained for the slower deposition rates, and the positive values for the faster rates. All of the TCC data agreed qualitatively with the Gevers–du Pre theory, suggesting that the negative TCC’s are due to large expansion coefficients and small film densities obtained at slow deposition rates. The results of the present study also suggest that zero TCC’s can be obtained for SiO films by precise control of the deposition rate.