Trapping of electrons in metal oxide-polymer memory diodes in the initial stage of electroforming

Metal oxide-polymer diodes require electroforming before they act as nonvolatile resistive switching memory diodes. Here we investigate the early stages of the electroforming process in Al/Al(2)O(3)/poly(spirofluorene)/Ba/Al diodes using quasistatic capacitance-voltage measurements. In the initial stage, electrons are injected into the polymer and then deeply trapped near the poly(spirofluorene)-Al(2)O(3) interface. For bias voltages below 6 V, the number of trapped electrons is found to be C(oxide)V/q with C(oxide) as the geometrical capacitance of the oxide layer. This implies a density of traps for the electrons at the polymer-metal oxide interface larger than 3 X 10(17) m(-2). (C) 2010 American Institute of Physics. [doi:10.1063/1.3520517]