Electronic structure of silicon oxynitride films grown by plasma-enhanced chemical vapor deposition for memristor application

• The plasma power effect on Si-rich PECVD SiO x N y :H electronic structure is studied. • An increase in plasma generator power leads to a decrease in the content of Si and O. • The a-Si/SiO x N y interface energy diagram is constructed within DFT simulation. • The studied films are suitable for the use as active medium of a forming-free RRAM. The electronic structure and optical properties of SiO x N y :H films enriched with silicon obtained by plasma-enhanced chemical deposition are studied. It is shown, that with the plasma generator power growth, the content of silicon (amorphous silicon clusters) and oxygen decreases, whereas the nitrogen content increases. Thus, the SiO x N y :H film composition can be effectively varied both by changing the gas flow ratio in the growth chamber and by changing the plasma generator power. The electronic stricture of SiO x N y of various x and y values is calculated from the first principles for the model structures, and the energy diagram, as well as the bandgap dependence on the oxygen content, is obtained. It is found that p + -Si/SiO x N y :H/Ni structures, have the properties of memristor bipolar type: they are reversibly switched between high and low resistance states. These memristors are forming-free: the initial state has a close resistance to the low resistance state.