Electrical properties of Al-SiO2Si structure with plasmochemical insulator: Potential barrier heights and electron capture in SiO2

It is shown that in the forbidden band of the plasmochemical SiO2 there are electron capture centers with capture cross section 2·10−13cm2, density 2·1019 cm−3, and thermal activation energy 0.41 eV for the process of trap emptying. It is noted that the charge state of the insulator in an external electric field is unstable, this being due to the exchange of electrons between the insulator and the aluminum electrode. An energy band diagram of the structure is deduced from the results of the investigation. The potential barrier heights were found to be 2.78 eV at the Al-SiO2 interface and 4.36 eV at the SiO2-Si interface. The dynamical current-voltage characteristic of the structure is used to determine the density of mobile ions in the insulator, which is found to be S·1013 cm−2 at T=230°C and rate of change 5 mV/sec of the voltage.