The chemical composition and structure of Si 3 N 4 /thermal ͑native and wet͒ SiO 2 interface in oxidenitride-oxide structures are studied by using secondary ion mass spectroscopy, electron energy loss spectroscopy ͑EELS͒ and Auger electron spectroscopy ͑AES͒ measurements. EELS and AES experiments show the existence of excess silicon at the Si 3 N 4 /thermal SiO 2 interface. Excess silicon ͑Si-Si bonds͒ at Si 3 N 4 /SiO 2 interface exists in the form of Si-rich silicon oxynitride. Numerical simulation of the Si-Si bond's electronic structure by using semiempirical quantum-chemical method ͑MINDO/3͒ shows that Si-Si defects act as either electron or hole traps. This result explains the abnormally large electron and hole capturing at this interface reported earlier.

The charge transport mechanism in amorphous Al 2 O 3 was examined both experimentally and theoretically. We have found that electrons are dominant charge carriers in Al 2 O 3. A satisfactory agreement between the experimental and calculated data was obtained assuming the multiphonon ionization mechanism for deep traps in Al 2 O 3. For the thermal and optical trap ionization energies in Al 2 O 3 , the values W T = 1.5 eV and W opt = 3.0 eV were obtained.

No abstract

No abstract

The charge transport in the amorphous Si 3 N 4 is studied experimentally and theoretically. We have found, that widely accepted Frenkel model of the trap ionization gives the unphysical low value of the attempt to escape factor, and the enormously high value of the electron tunnel mass. Experimental data are well described by theory of the two-bands conduction and the phonon-assisted trap ionization in Si 3 N 4 .