Short-range order and charge transport in silicon-rich pyrolytic silicon oxynitride

Amorphous SiOxNy films were grown by pyrolysis in a reduced pressure reactor at T = 800 °C for different SiH2Cl2/NH3 ratios from 1/5 to 1/1. The resulting analysis for the photoelectron spectra showed that, in addition to silicon and nitrogen, the samples composition includes oxygen, apparently, due to the presence of residual traces of oxygen and/or water. The red shift of the fundamental absorption edge indicates the presence of Si-Si bonds in SiOxNy. In a wide range of electric fields and temperatures, the charge transport mechanisms in SiOxNy are experimentally studied. The experimental results are compared with the calculation based on different trap ionization models. The best agreement between the experiment and calculation was obtained using the model of phonon-assisted tunneling between neighboring traps. The increase in the SiOxNy leakage current, when changing the SiH2Cl2/NH3 ratio from 1/5 to 1/1, is explained by the trap concentration increase.